cat Install Guide

TruckApplication andInstallationGuide

LEBT5109-01 6-98

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Caterpillar Truck EnginesApplication & Installation Guide

Table of Contents

Introduction .......................................................................................3

Trucks, Engines, and Applications...............................................4

Engine Selection ...............................................................................8

Performance and Operating Checks.........................................13

Air Intake System ...........................................................................17

Exhaust System ...............................................................................22

Fuel System.......................................................................................26

Lubrication System ........................................................................33

Cooling System ................................................................................39

Air-to-Air AfterCooling System...................................................68

Starting Electrical System ...........................................................73

Governor and Controls..................................................................80

Support System ...............................................................................83

Alignment and Torsionals.............................................................88

Auxiliary Braking Devices ...........................................................90

Emissions Noise and Gaseous .....................................................98

Serviceability Guidelines ...........................................................101

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INTRODUCTIONThis booklet is a basic reference and guide forthe correct application and installation ofCaterpillar Engines in trucks and buses. Itsprimary purpose is to assist engineers anddesigners specializing in engine selection,application and installation. The TruckEngine Installation Drawings, TruckElectronic Application and Installation Guide,and Truck Engine Performance bookletscomplement this booklet.

ENGINE INSTALLATION AND TECHNICAL REVIEWCaterpillar Engines are designed and built toprovide superior value; however, achieving theend user’s value expectations depends greatlyon the performance of the entire power trainconsisting of various components andsystems, of which the engine is only one part,albeit a vital part.

In order to validate the engine performanceand better assure end user satisfaction,Caterpillar requires a mandatory technicalreview of OEM customers' initial engineinstallation as a prerequisite to the sale ofengines on an outgoing basis. Additionally, areview is necessary whenever a change ismade to the installation which might affectthe engine’s overall performance. It is theOEM’s responsibility to inform Caterpillarwhen such changes are made.

This review is performed by the OEMspersonnel at their facilities with qualified

Caterpillar technical personnel assisting on afree-of-charge basis. Particular attention isgiven to cooling, air intake and exhaust, fuel,electronic and electrical systems, mountingand mechanical drives, serviceability, andoperator safety. A copy of Caterpillar’sinstallation review report is provided to theOEM. The review report documents theimportant features and details of the engineinstallation and indicates thosecharacteristics judged satisfactory,unsatisfactory, and likely to lead to userdissatisfaction, or marginally satisfactory,depending on the extremes of the operatingenvironment. The review report willrecommend improvements to the installationas appropriate.

Although Caterpillar exercises all reasonableeffort to assure engines perform properly inthe OEMs equipment, the responsibility forthe engine installation is the OEMs, andCaterpillar assumes no responsibility fordeficiencies in the installation.

It is the installer’s responsibility to considerand avoid possibly hazardous conditionswhich could develop from the systems involvedin the specific engine installation. Thesuggestions provided in this guide regardingavoidance of hazardous conditions apply to allapplications and are necessarily of a generalnature since only the installer is familiar withthe details of his installation. The suggestionsprovided in this guide should be consideredgeneral examples only and are in no wayintended to cover every possible hazard inevery installation.

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Trucks, Engines, and Applications

Types of Engines and Trucks...........................................................5Application Severity ..........................................................................5

Loaded Factor (Average Fuel Consumption)................................5Engine Operation per Shift ............................................................6Average Travel Speed...................................................................6Type of Operation ..........................................................................6Miles Traveled per Shift .................................................................6Annual Mileage ..............................................................................6Gross Weight .................................................................................7Average Gross Weight Load Factor..............................................7

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TYPES OF ENGINES AND TRUCKSCaterpillar Truck Engines are designed tomeet the specific performance requirements oftwo general, but distinct types of truckapplications. Depending on the severity of theapplication, they are medium-duty orheavy-duty engines.

Other terms, many descriptive of theapplication or chassis, and regional in nature,are used to indicate the type of truck. To avoidthe limitations and inconsistency of terms,only medium and heavy-duty terminology isused in this manual.

APPLICATION SEVERITYTruck engines and trucks are designed for theseverity of an application. Severity refers tohow hard the engine and truck must work toget the job done or the performance demandedby the application. Severity can easily bedetermined by identifying eight applicationfactors.

Application Factors or ConditionsFactors Determining Application Severity:

• Average fuel consumption (% load factor)• Engine operation per shift• Average travel speed• Type of operation• Miles traveled per shift• Annual mileage• Gross vehicle weight• Ratio of average GVW to maximum GVW

Load Factor (Average Fuel Consumption)Average fuel consumption is a means ofdetermining the average horsepowerproduced by the engine. To make average fuelconsumption and horsepower meaningful interms of how hard the engine is working, bothare stated as load factor. Load factor iscalculated with this formula:average fuel rate (gal/hr) x 100 = Load Factor (in %)

maximum fuel rate (gal/hr)

To illustrate the load factor formula, assumean engine is rated 210 hp. Dynamometer testsof specific fuel consumption show it willconsume a maximum of 12 U.S. gallons of fuelper hour when operated continuously at210 hp. This is the maximum fuel rate.

The average fuel rate is the volume of the fuelconsumed during a typical cycle of theapplication. This requires accuratemeasurement of fuel consumption for acomplete operating cycle, including no load aswell as maximum load.

Continuing the example, the average fuel rateof the 210 hp engine is measured at 4 gallonsper hour. The calculations look like this:

average fuel rate x 100 = 4 gal/hr x 100 = 33% Load Factormaximum fuel rate 12 gal/hr

From this, the average horsepower developedis calculated by multiplying the 210 rated hpby the 33% load factor for 70 hp.

This example indicates a light application. Ifthe average fuel rate had been 10 gallons offuel per hour, load factor would be 83% withan average of 174 hp, constituting a severeapplication.

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Engine Operation per Shift (8-10 Hours)Heavy-duty vehicles often operate 80-100% ofan 8-10 hour shift. Because medium-dutyvehicles may make frequent stops or arerequired to wait long periods to load orunload, the actual operating time per shiftwill be 50-90%.

Modern fuel saving techniques dictate theengine be shut off if the idle time per stop is inexcess of 5 minutes. Exceptions to the rule arefor driver comfort in cold or warm climates, inconstruction work where the vehicles arecalled on to move a short distance frequently,or if power takeoff operation is required withthe vehicle at rest.

Average Travel SpeedAverage travel speed is calculated by thefollowing equation.

Miles Traveled per Shift = Average Travel Speed

Travel Time in Hours

Do not include idle time and engine shutofftime in travel time.

High average travel speed indicates few stopswere made and a high cruising speed.Together these can result in high horsepowerdemands and high load factors.

Type of OperationThe following are examples of types ofoperation ordered from light medium-duty tosevere heavy-duty conditions.

a. Central city pickup and delivery.b. Suburban (intra-city) pickup and delivery.c. Two-lane highway under 55 mph

speed limit (88 km/h).d. Two-lane highway 55 mph speed limit

(88 km/h).e. Freeway or Interstate under 55 mph

speed limit (88 km/h).f. Freeway or Interstate 55 mph

or over speed limit (88 km/h).

Examples a and b are strictly stop-and-goservice with low average travel speeds andlow percent engine operation per shift.Gearing frequently is low for goodacceleration and payloads vary due todeliveries and pickups. Often, the trucktravels empty.

Examples c and d have higher horsepowerdemands and load factors. The trucks areprobably geared for higher speeds withminimal stops, resulting in higher averagetravel speeds. Unless there are offsettingfactors, such as low GVW or frequent stops,these applications could be heavy-duty.

Examples e and f are typical of heavy-dutyapplications and must be carefully examinedto determine whether the high speedhorsepower demands are sufficiently offset bylow GVW, low percent engine operation pershift, or other conditions making theapplication suitable for a medium-dutyengine.

Miles Traveled per Shift (8-10 Hours)Shift mileage is a good check on other aspectsof an application. High cruising speeds, forexample, and low mileage per shift seldomoccur together.

Annual MileageHigh annual mileage (above 70,000 miles) istypical of heavy-duty trucks. They travel atuninterrupted high speeds between cities.There are exceptions, usually heavy-dutyconstruction trucks, such as dump or transitmixer trucks.

Medium-duty truck annual mileage generallyis 12,000-60,000 miles (19,000-97,000 km).This is due to low average speeds and stop-and-go operations; however, engine hours ofoperation are substantial. Medium-dutytrucks have lower mileage life compared toheavy-duty trucks. High daily mileage couldcause unacceptably short overhaul periodseven though performance and economyotherwise are excellent.

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Gross WeightGross weight must be limited in medium-dutyapplications to keep load or horsepowerdemand on the engine at an acceptable level.Depending on the type of truck, van, trailer,dump or transit mixer, the normal permissiblegross weight ranges from 20,000 lbs. to legallimits. The permissible gross weight isinversely proportional to maximum travelspeed. The higher the speed, the lower thepermissible gross weight, and vice versa.

There is no application restriction on thegross weight of medium-duty or heavy-dutyengines other than legal weight. Minimumhorsepower, to ensure the engine has enoughhorsepower to move the load at the desiredspeed, is sometimes a consideration.

Average Gross Weight Load FactorAverage gross weight load factor is calculatedby the following equation.

The load factor is the percent of time a truckoperates partially loaded. Medium-dutytrucks make deliveries or pick up loadsenroute and seldom operate at full load. Manytravel empty one way. Heavy-duty trucks areusually loaded all of the time. Tankers andconstruction trucks are exceptions.

A balance of performance and economycoupled with vehicle initial investment, tradecycle, and residual value influence selection ofthe appropriate engine rating. Consultindividual engine specification sheets orcatalogs for specific rating recommendationsor limits.

Load Factor =Empty Truck Weight + Average Payload x 100

Empty Truck Weight + Maximum Payload

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Engine Selection

General Procedure ...........................................................................9Horsepower Requirements ..............................................................9Measuring Truck Performance.........................................................9

Maximum Road Speed..................................................................9Cruising Road Speed ....................................................................9Gradeability (percent) ..................................................................10Startability (percent).....................................................................10

Calculating Horsepower Requirements .........................................10Drive Train Losses.......................................................................10Air Resistance Horsepower.........................................................10Rolling Resistance Horsepower ..................................................11Grade Resistance Horsepower ...................................................11

Engine Selection and Powertrain Checklist ...................................11Gross Horsepower.......................................................................11Net Horsepower ...........................................................................11Transmission Speed Ranges ......................................................11Startability and Gradeability Requirements.................................11Proper Engine Application ...........................................................11

Engine Ratings................................................................................11Truck Performance Computer Program.........................................11Market Area.....................................................................................11

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GENERAL PROCEDUREAfter identifying the application as instructedin Section A, determining the horsepowerrequired will help in selecting the correctengine. The horsepower required by theapplication selection alone can dictate aheavy-duty engine. If it exceeds medium-dutyengine ratings, a heavy-duty engine must beused. If the required horsepower falls withinthe medium-duty range, the application mustbe taken into account. First, verify that therating being used is neither too large norsmall for the application.

HORSEPOWER REQUIREMENTSSelecting an engine with enough, but not toomuch, horsepower to provide the performancespecified by the customer involves looking atthe entire powertrain. For brevity in thesection, it is assumed that powertrain factorsother than those affecting horsepower havebeen correctly matched to the engine.

MEASURING TRUCK PERFORMANCERegardless of how the horsepower for anapplication is determined, the determinationmust be made in terms of the following fourmeasures of truck performance.

Maximum Road Speed (mph)This is the maximum attainable road speedfor the conditions under which the truck willoperate.

Road speed is often improperly assessed. Atop speed may be demanded that is illegal oreconomically impractical from an applicationstandpoint. If a certain speed cannot beproduced from a powertrain, the engine isusually blamed for lack of power. When otherfactors such as less startability due to highergear speed or wind resistance, the followingfactors must be considered in making thismeasure.

Load may be the cause. The heavier thevehicle the less speed attainable for the sameset of conditions and net engine horsepower.

Road Conditions: These are not as importantfor on-highway applications. Most vehiclesoperate on first class highways or Interstates.For those trucks operating both on-offhighway, or completely off-highway, roadconditions are a very important consideration.

Wind: A small increase over an already highspeed greatly increases the horsepowerneeded to overcome wind resistance. Verticalside ribs on the body or van have higher windresistance than do horizontal and smoothsided vans. An open load such as a car carriercan have from 50 to 100% more windresistance than an enclosed van. Prevailingwinds are usually considered insignificant,but their effect is the same as increasing theroad speed. More horsepower is needed andtravel speeds can be decreased by head winds.

Altitude: Operating in higher altitudes canreduce performance because it limits airintake by the engine. Naturally aspiratedengines lose about 3% of their grosshorsepower for each 1000 feet rise above sealevel. Caterpillar turbocharged engines can gohigher in altitude before derating becomesnecessary. For specific derations of CaterpillarEngines, check the Truck Engine Data Sheet.

Cruising Road Speed (mph) This is the speed (rpm) an engine is operatingat while achieving good fuel economy. ForCaterpillar Truck Engines, this rpm isbetween 10 to 20% below rated or governedrpm. In certain very fuel efficientspecifications, this rpm could be as low as 40%of rated rpm. The balanced performancepowertrain allows the engine to operate atleast 10% below rated speed in direct drive oroverdrive with the truck traveling at thedesired or legal speed limit. Maximum roadspeed is reserved for passing and gainingmomentum for climbing hills. Cruising speedhorsepower requirements must be calculatedwhile considering the factors affectingmaximum road speed horsepower.

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Gradeability (percent)This is the maximum grade the truck cannegotiate at a given speed.

Gradeability is easy to measure in a vehiclebut difficult to select and apply. Under a givenset of conditions one can easily determine justhow steep a grade a vehicle can negotiate. It isof more interest, however, to know just howfast a truck can climb grades encounteredover a specific route. This is important to theowner due to the effect of grades on trip times.

Wind, depending upon the speed a grade isnegotiated, can be a significant factor whenconsidering gradeability.

Startability (percent)This is the ability to start the load movingfrom a dead stop, based on the most severeconditions under which the truck will operate.

Startability of a truck is directly related to itstotal gearing ratios. Good startability andproper speed ratios don’t just happen, theyare the result of planning.

Startability is affected greatly by conditions ofload and grade. As the load becomes heavierand the grade steeper, the problem ismagnified proportionally. Gradeabilitycalculations are based on maximum torquewhile startability is a function of torqueavailable in the low speed range of 800-1000 rpm. The minimum gradestartability in first gear should beapproximately 10% for general purposelinehaul vehicles and considerably greaterfor vehicles in on/off-highway service (15%minimum). Some applications may beadequate with a grade startability between6% to 10% but should be reviewed. Theabsolute minimum for any vehicle should be 6%.

CALCULATING HORSEPOWERREQUIREMENTS A variety of means is available for calculatinggross and net horsepower demand. Whennone of these are available, use the followingformula to check horsepower requirements atany speed and grade. The horsepowerrequired is the sum of the followingcomponents:• Total drivetrain loss.• Air resistance.• Rolling resistance.• Grade resistance.Horsepower required at the flywheel equalsthe sum of the following:

Drive Train Losses = (1-Driveline Efficiency) x (hpA + hpRR + hpG)

hpA = Air Resistance Horsepower

hpRR

= Rolling Resistance Horsepower

hpG = Grade Resistance Horsepower

There is a 3-5% loss in horsepower throughevery component of the drive train. Thus, ifthe vehicle has a main transmission, auxiliarytransmission, and a single rear axle, thedriveline efficiency is 0.88 (0.96 x 0.96 x 0.96).

Air Resistance Horsepower =mph3

x 0.00172 x Frontal Area x Modifier375

mph = miles per hour

Frontal Area = Width in ft x (height in ft minus 0.75 ft)

Modifier: If an aerodynamic improvementdevice or system is used on a typical freightvan, the modifier is 0.60. If no device is used,the modifier is 1.0. As truck aerodynamicsimprove, the modifier may decrease to lessthan 0.60.

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Rolling Resistance Horsepower = COR x GVW or GCW x mph

750,000

COR = Coefficient of rolling resistance inpounds horizontal force/ton of vehicle weight.For Example: On good concrete, bias ply tireshave a rolling resistance of 17 lb/ton andradial tires 11 lb/ton. Low profile tires canresult in even lower rolling resistance.

GVW or GCW = Gross weight of the vehicle inpounds.

Grade Resistance Horsepower = Grade x GVW or GCW x mph

37,500

Grade = Slope of road expressed as a percent.

ENGINE SELECTION AND POWERTRAIN CHECKLIST

Gross HorsepowerGross or rated horsepower is adequate foraccessory load and required net flywheelhorsepower requirements at maximum roadspeed under normal conditions.

Net HorsepowerNet flywheel horsepower is adequate atcruising speed under normal operatingconditions. To check this, determine thehorsepower available at approximately 10to 20% below rated speed from the engineperformance curves.

Transmission Speed RangesTransmission has sufficient speed ranges sothat the engine rpm does not fall below peaktorque rpm when shifting to the next higherrange at speeds above 30 mph. At road speedsbelow 30 mph, the demand horsepower isusually so low that engine operation belowpeak rpm is acceptable.

Startability and GradeabilityStartability and gradeability meet or exceedminimum requirement.

Proper Engine ApplicationEngine is proper for the application, heavy-duty or medium-duty.

ENGINE RATINGSPerformance curves for Caterpillar TruckEngines are contained in the Truck EnginePerformance book. Similar performancecurves appear on the specification sheets foreach model.

All Caterpillar Truck Engines are rated underthese conditions.

Without fan unless specified otherwise on theperformance curve.

Standard SAE J1995 conditions of 29.3 in. (99 kPa) Hg and 77°F (25°C).

Fuel oil having a gross heat value of 18,390 Btu per pound (42,780 kJ/kg), weightof 7.001 lb/U.S. gal (838.9 g/L).

Standard engine equipped with fuel,lubricating, water pumps, and air compressor.Both heavy-duty engines and medium-dutyengines are rated without air cleaner, fan andalternator.

Gross flywheel horsepower under the aboveconditions are within a nominal tolerance of ±3%.

TRUCK PERFORMANCE COMPUTER PROGRAMCaterpillar offers personal computer basedsoftware, Cat Truck Engine Pro forestablishing the expected performance of aselected powertrain.

MARKET AREADue primarily to the availability of differenttypes of oil in the world the following chartshows where various configurations of the3116/3126 engine should be marketed.

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Regulated Markets

(3)Africa, Russia

U.S. South Middle Markets & CISCanada America East with CD Oil

Australia (Requiring and CF4/ orEngine New Zealand Mexico Euro Cert) Far East Europe CG4 Oil Poorer

3116 MUI N/A N/A Y Y Y Y Y• EURO II Certified• 2 MICR Fuel Filter• Loose Top Land Piston

3116 HEUI/3126 N/A N/A Y Y Y Y N• EURO II Certified (5)• 2 MICR Fuel Filter• Tight Top Land Piston

3116 HEUI/3126B Y (2) N/A (2) N/A (2) N/A• EPA Certified• 2 MICR Fuel Filter• Tight Top Land Piston

Truck RequirementsPrimary Fuel Filter (4) Req’d Req’d Req’d Req’d Req’d Req’d Req’dWater Separator Recom. Req’d Req’d Req’d Recom. Req’d Req’d

Notes

1) CF4/CG4 multiviscosity oil required for all engines as stated in the operation and maintenance manual.

2) Do not sell unless CF4/CG4 multiviscosity availability is assured.

3) 3,000 mile oil change period and additional oil sump capacity is required when using typical Russian oil.28L required for 200 HP and below, 39L required for 250 HP. For other ratings contact the 3116/3126 product group.

4) Primary fuel filter specification; 200 gram minimum sediment capacity (SAE J905) with 150 or lessmicron rating. When applied in locations where particularly dirty fuel is expected to be encountered,consult the factory.

5) The total rotating inertia of the transmission and accessories must be verified by the OEM to be withinthe certified range. Euro certification is not available for direct drive fans.

3116/3126 Truck EngineMarket Area (1)

Performance and Operating Checks

General ...........................................................................................14Initial Start-up Checklist..................................................................14

Before Starting Engine ................................................................14General InspectionEngine Coolant LevelCrankcase Oil LevelDepress Clutch

After Starting Engine....................................................................14General InspectionEngine Oil PressureEngine Coolant LevelLeaksUnusual SoundsAccelerate Engine SlowlyAcceptance Test

General Operating Procedures ......................................................15Break-in PeriodContinuous at Rated SpeedLugging the EngineDisassembly and Assembly

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GENERALThis chapter is designed to answer basicquestions about initial start-up in the factoryto operating techniques on the road. Itsupplements the operating instructions andtroubleshooting guides and performancecheck lists in the Caterpillar Truck EngineOperation and Maintenance Management andService Manuals. If more data of this type isneeded, it can be found in these publications.They can be ordered from your localauthorized Caterpillar Dealer.

INITIAL START-UP CHECKLISTBefore starting an engine for the first time,check these items in sequence.

Be sure the first three are checked by theperson actuating the starter switch. It’s theonly way to avoid finding out too late thatsomeone overlooked the following criticalpoints.

Before Starting the Engine:General InspectionVisually check entire installation. Carefully check for loose oil and water lines, fittings and loose belts.

Engine Coolant LevelIf radiator was filled sometime before start-up, recheck in case the radiator was only partially filled. Caterpillar Engines will fill, but the radiator and piping added to the system may have a tendency to give a false fill. It, therefore, is recommended that the radiator always be checked after the initial fill (and every fill thereafter) to make sure the radiator and engine are full of coolant.

Crankcase Oil LevelCheck both sides of the dipstick, as some have markings on both sides. One side is for checking the level with the engine stopped; the other side is for checking the level when the engine is running. If the marking is for checking oil level when running, the oil level

will be above the full mark when the engine is stopped. Refer to the Truck Engine Data Sheet for the correct type, grade and weight of oil.

Depress ClutchDepress the clutch to remove transmission load from the starter motor.

After Starting Engine:General InspectionAfter the engine has been started, check the following points while the engine idles and warms up.

Engine Oil PressureStop engine immediately if no pressure is indicated and determine cause before restarting. See Truck Engine Data Sheet for minimum oil pressures.

Engine Coolant LevelCheck coolant level. Refill to proper level if low. (Be sure to first release cooling system pressure.)

LeaksCheck for oil and water leaks.

Unusual SoundsListen for abnormal sounds or unusual noise.

Accelerate Engine SlowlySlowly accelerate engine to high idle. Continue to check for leaks, vibration, excessive noise, etc. Check throttle linkage for proper adjustment. Broken link must deflect at the high idle position on mechanically governed engines.

Acceptance TestMake needed adjustments and run your required acceptance tests. If dynamometer testing is required, thoroughly warm up the engine by running at part load and speed for about 15 minutes. Observe coolant temperature while under load.

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GENERAL OPERATINGPROCEDURESComprehensive operating instructions arecontained in the Operation and MaintenanceManagement Manual provided with everyengine. After reading the instructions, ownersoften ask, "Is this really important?" Themost frequent questions of this type areanswered below.

Break-in PeriodEvery Caterpillar engine must pass a full loadoperation test on a dynamometer beforeshipment, eliminating the need for a break-inperiod. Only an initial operational check isnecessary. Its purpose is to insure the enginehas been assembled properly, determining ifproper pressures and temperatures aremaintained, correct any leaks, and performnecessary adjustments, such as throttlelinkage.

Continuous at Rated SpeedWill operating continuously at rated speeddamage the engine? This question is a resultof the recommendation to operate (cruise)

approximately 20% to 40% below rated speed,for maximum fuel economy. Caterpillarengines can operate continuously at full ratedspeed. Lower fuel economy (higher fuelconsumption) is the penalty.

Lugging the EngineCaterpillar truck engines have good luggingcharacteristics with maximum torqueoccurring at 50-70% of rated speed.Turbocharged engines can be lugged down topeak torque before down shifting. Runningcontinuously at peak torque rpm at full loadwill not damage turbocharged Caterpillarengines.

Disassembly and AssemblyDuring the course of an installation, someexternal bolt and part probably will beadjusted, loosened, or removed. The questionthen is how tight should the bolt(s) be. OnCaterpillar engines this problem is simplifiedby using only Grade 8 bolts. TightenCaterpillar supplied bolts to the values givenin Figure 1.

Metric Taperlock Studs

M6

M8

M10

M12

M16

M20

M24

M30

M36

8 ± 3

17 ± 5

35 ± 5

65 ± 10

110 ± 20

170 ± 30

400 ± 60

750 ± 80

1200 ± 150

6 ± 2

13 ± 4

26 ± 4

48 ± 7

80 ± 15

125 ± 22

300 ± 45

550 ± 60

890 ± 110

Standard Torque

N•m lb ft

Thread Size

Metric Nuts and Bolts

M6

M8

M10

M12

M14

M16

M20

M24

M30

M36

12 ± 3

28 ± 7

55 ± 10

100 ± 20

160 ± 30

240 ± 40

460 ± 60

800 ± 100

1600 ± 200

2700 ± 300

9 ± 2

20 ± 5

40 ± 7

75 ± 15

120 ± 22

175 ± 30

340 ± 45

600 ± 75

1200 ± 150

2000 ± 225

Standard Torque

N•m lb ft

Thread Size

Figure 1

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Exceptions to these torques are given in theService Manual where needed.

Note: Prior to installation of any hardware, besure components are in near new condition.Bolt and threads must not be worn ordamaged. Hardware must be free of rust andcorrosion. Clean hardware with a non-corrosive cleaner and apply engine oil tothreads and bearing face. If thread lock orother compounds are to be applied, do notapply engine oil.

Standard Torque for Inch FastenersExceptions to these torques are given in theService Manual where needed.

When a bolt secures an internal part, or is ona rotating part, it could require a specialtorque. Whenever this situation arises, alwayscheck the engine’s service manual or consultwith Caterpillar Engineering forrecommended tightening torque.

When adding brackets to an engine, be sure touse bolts of the correct length. Existing boltscould be too short and may not have enoughthreads to hold the part securely. A bolt whichis too long may bottom before the seat is tightagainst the part. The threads in the assemblycan also be damaged when a long bolt is used.It is not recommended to remove bolts from agasketed joint for clipping or adding brackets.

Installation (or removal) of an engine shouldbe accomplished by using a lifting beam orspreader bar. All supports (chains and cables)should be parallel to each other and as nearlyperpendicular as possible to the top of theengine as shown in Figure 2.

Figure 2

Inch Nuts and Bolts

1/45/16

3/87/16

1/29/16

5/83/47/8

1

11/8

11/4

13/8

11/2

12 ± 3

25 ± 6

47 ± 9

70 ± 15

105 ± 20

160 ± 30

215 ± 40

370 ± 50

620 ± 80

900 ± 100

1300 ± 150

1800 ± 200

2400 ± 300

3100 ± 350

9 ± 2

18 ± 4.5

35 ± 7

50 ± 11

75 ± 15

120 ± 20

160 ± 30

275 ± 35

460 ± 60

660 ± 75

950 ± 100

1325 ± 150

1800 ± 225

2300 ± 250

Standard Torque

N•m lb ft

Thread Size

Inch Taperlock Studs

1/45/16

3/87/16

1/25/83/47/8

1

11/8

11/4

13/8

11/2

8 ± 3

17 ± 5

35 ± 5

45 ± 10

65 ± 10

110 ± 20

170 ± 30

260 ± 40

400 ± 60

525 ± 60

750 ± 80

950 ± 125

1200 ± 150

6 ± 2

13 ± 4

26 ± 4

33 ± 7

48 ± 7

80 ± 15

125 ± 22

190 ± 30

300 ± 45

390 ± 45

550 ± 60

700 ± 92

890 ± 110

Standard Torque

N•m lb ft

Thread Size

Figure 1 (continued)

Standard Torque for MetricFastenersNote: Take care to avoid mixing metric andinch dimensioned fasteners. Mismatched orincorrect fasteners can result in vehicledamage or malfunction, or possible injury.

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Air Intake System

General Requirements ...................................................................18Air Cleaner ......................................................................................18

Service Life ..................................................................................18Air FlowRestrictionService Indicator

Air Cleaner Efficiency ..................................................................19Performance TestDust Particle Size EffectsTwo-stage Air CleanersOil Bath Air Cleaner

System............................................................................................20Intake............................................................................................20System Design.............................................................................20

RoutingDiameterFlexibilityPipe Ends and Hose ConnectionsBreakaway JointsPiping SupportStraight Section Before Turbocharger

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GENERAL REQUIREMENTSThe function of the air intake system is tofurnish an adequate supply of clean, dry, lowtemperature air to the engine. Failing this,increased maintenance costs and/orperformance problems are certain to result.The following recommendations must beobserved in order to obtain a satisfactoryinstallation:

Every installation must include an efficientprovision for removing dirt particles from theintake air.

The air inlet location and piping routing mustbe chosen to best obtain cool air. All jointsshould be air tight and all pipes properlysupported. The air inlet must be designed tominimize the ingestion of water from rainstorms, road splash, or the vehicle washingprocess.

The system maximum air restriction caneffect engine emissions and must not beexceeded. For specific engine limits see theTruck Engine Data Sheet.

If breakaway pipe joints are used, they mustbe located upstream of the air cleaner.

AIR CLEANERDirt is the basic source of engine wear. Mostdirt enters the engine via the inlet air.Cylinder walls or liners, pistons, piston rings,valves, valve guides and, in fact, any enginemoving part is subjected to accelerated wearwhen undue amounts of dirt are contained inthe inlet air. Therefore, careful air cleanerselection is vital to a good engine installation.

Dry-type air cleaners are recommended forCaterpillar Truck Engines.

The following information will be of help whendesigning an air cleaner system forCaterpillar Engines.

Service LifeThe air cleaner must be sized so that initialrestriction is low enough to give acceptablelife within the maximum allowable restrictionof the air inlet system.

Air FlowRefer to the Truck Engine Data Sheet. Thevalue given as combustion air flow is for fullload Bhp at SAE conditions.

RestrictionPressure drop across a typical air cleaner willbe 6.0 in. H2O when clean. The piping systemmight typically add another 3.0 in. H2Opressure drop. For maximum permissible airrestriction for a dirty air cleaner element referto the Truck Engine Data Sheet. To provide forsatisfactory engine performance and adequatefilter element service life, the element shouldbe sized as large as practical. The 9.0 in. H2Oinitial pressure drop is an important measureof the expected element service life. Generally,the maximum initial (clean dry) restrictionrecommendation is 15 in. H2O. See the TruckEngine Data Sheet for specific engine limits.

Service IndicatorVacuum sensing devices designed to indicatethe need for air cleaner servicing arecommercially available and when added to theair intake system, serve a vital function. Oneof the following types is recommended for use:

• The trip lock device which indicates that theair cleaner condition is either satisfactory orwhen in need of service; it has has a reddisplay. The device is preset to indicatewhen filter service is needed.

• The latching type device that always latchesat graduated levels of inlet restriction. Thedevice measures restriction in inches ofwater vacuum and signals not only whenengine is on but when the engine is shutdown, so operator can check filter conditionat any time.

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• The third type is the direct reading gauge(usually in the cab) that indicates inches ofwater vacuum, when the engine is inoperation.

One of the above service indicators should beconnected in the air piping from the aircleaner to the turbocharger, near theturbocharger. If the indicator is mounted onthe air cleaner, the setting should be adjustedto indicate need for service before the point ofmaximum system restriction is reached (sinceadditional piping restriction is encountereddownstream of the air cleaner).

Air Cleaner EfficiencyThe air cleaner selection should be basedupon the following efficiency considerations:

Performance TestA satisfactory air cleaner must meet therequirements of the SAE Air Cleaner TestCode J726, Section 3. The filter must have99.5% efficiency minimum as calculated bythis test code with additions and exceptions asfollows:

• Air flow corrected to ft3/min. at 29.61 in. Hg(100 kPa) pressure and 77°F (25°C).

• Use sonic dust feeder.• Use Powder Technology Inc. (PTI) fine dust.• Filter to be dried and weighed in an oven at

225±5°F (107±2°C) before and after test.

99.5% filtration of the PTI fine dust has beendetermined to be a practical combination ofthe kind of dirt likely encountered in over-the-road service at an air cleaner efficiencyexpected to give optimum engine wear life.

Dust Particle Size EffectsThe above test procedure will haveestablished sufficient control on the filtermedia particle size filtering ability of thetested air cleaner. Variables needing furthercontrol include:

• Choose filters supplied by manufacturersthat can best provide quality control.

• Filters should be designed to be resistant todamage at initial assembly or duringcleaning. End seal and filter media both aresubject to damage which can result in dustleakage into the engine.

• Dirt can be built into the piping at initialassembly, enter the system during the filterchange or be sucked into leaks in the pipingsystem.

Two-Stage Air CleanersFor conditions in which dust concentrationsare higher or increased service life is desired,air cleaners are available with a precleaningstage. This precleaner imparts a swirl to theair, centrifuging out a major percentage of thedirt particles which may be collected in areservoir or exhausted out on either acontinuous or an intermittent basis.

Oil Bath Air CleanerOil bath air cleaners, while sometimesrequired to meet customer specifications, arenot recommended by Caterpillar. At best theirefficiency is 95% as compared to 99.5% fordry-type filters. In addition to being lessefficient, their relative ease of service andinsensitivity to water advantages are easilyoutweighed by disadvantages, such as:

• Low ambient temperatures, low oil level,low air flow (such as when truck is at lowidle) and truck tilt angle lessens efficiencyfurther.

• Oil carry over, whether resulting fromoverfilling or increased air flow, canseriously affect turbocharger and engine life.

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SYSTEMThe dry-type filter efficiency is not affectedby angle of orientation on the vehicle. Specialcare should be taken, though, in arrangingthe filter housing and the piping, to insurethat dirt retained in the filter housing is notinadvertently dumped into the engine airsupply by service personnel during the aircleaner service operation. A verticallymounted air cleaner with bottom mountedengine supply pipe would be particularlyvulnerable to this occurrence. For applicationsinvolving off-highway operation or extremelydusty conditions, a filter design incorporatinga secondary or safety element which remainsundisturbed during many change periodsshould be used. Its higher initial cost is offsetby its contribution to longer engine life.

IntakeThe air inlet should be shielded against directentrance of rain or snow. The most commonpractice is to provide a cap or inlet hood whichincorporates a coarse screen to keep out largeobjects. This cap should be designed to keepair flow restriction to a minimum. Some usershave designed a front air intake which gives adirect air inlet and an internal means ofachieving water separation.

Precleaners and prescreeners incorporatedinto the intake cap design are also available.They can be used where special conditionsprevail or to increase the air cleaner servicelife. These devices can remove 70-80% of thedirt. The prescreener is designed to protectthe inlet system when trash is encountered.

System Design RoutingIn addition to locating the inlet so that coolestpossible air is used and engine exhaust gas isnot ingested, it is best to locate the pipingaway from the vicinity of the exhaust pipingwhen possible to do so. The maximumrecommended air temperature rise is 20°Fbetween ambient and the engine inlet(usually compressor inlet). (Example: 130°Fmaximum at 110°F ambient temperature).

Underhood air cleaners make this moredifficult to achieve but higher temperaturescan affect engine performance, as shown inFigure 3.

Higher air temperature can also affectturbocharger compressor wheel life,particularly at the high turbocharger speedsseen at altitude. The higher temperatures cangive lower intake manifold pressures whichresults in increased fuel consumption andslower response to a load change.

Every 1° rise in temperature to theturbocharger passes through the turbochargeras a 1° rise in temperature to the charge aircooler. Only 80-88% of this rise is removed bythe CAC, the remainder increases the intakemanifold temperature. This rise makes theCAC sizing more difficult. (See Air-to-AirAfterCooling Systems.)

DiameterPiping diameter should be equal to or largerthan the air cleaner inlet and outlet and theengine air inlet. A rough guide for pipe sizeselection would be to keep maximum airvelocity in the piping in the 2000-3000 fpmrange.

Figure 3

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FlexibilityTo allow for minor misalignment due tomanufacturing tolerances, engine to cabrelative movement and to isolate vibrations,segments of the piping should consist offlexible rubber fittings. These are designed foruse on diesel engine air intake systems andare commercially available. These fittingsinclude hose connectors and reducers, rubberelbows and a variety of special shapes. Wirereinforced flexible hose should not be used.Most material available is susceptible todamage from abrasion and abuse and is verydifficult to seal effectively at the clampingpoints unless special ends are provided onthe hose.

Pipe Ends and Hose ConnectionsBeaded pipe ends at hose joints arerecommended. Sealing surfaces should beround, smooth and free of burrs or sharpedges that could cut the hose. The tubingshould have sufficient strength to withstandthe hose clamping forces. Avoid the use ofplastic tubing since it can lose much of itsphysical properties when subjected to enginecompartment temperatures of up to 300°F.Either “T” bolt type or SAE type F hoseclamps providing a 360° seal should be used.They should be top quality clamps.

Breakaway Joints Breakaway joints may, if carefully designed,be used upstream of the air cleaner but neverbetween the air cleaner and engine. Whenbreakaway joints are required, choose a jointdesigned for lifetime sealing under the mostsevere conditions and needing little or nomaintenance.

Piping SupportBracing and supports are required for thepiping. The turbocharger inlet piping mustbe supported when its weight exceeds 20 lb-ft (27 Nm). Unsupported weight on clamp-typejoints should not exceed 3 lb (1.5 kg).

Straight Section Before TurbochargerWhen possible, the piping to the turbochargerinlet should be designed to insure that air isflowing in a straight uniform direction intothe turbocharger compressor. A straightsection of at least 2 or 3 times pipe diameteris recommended.

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Exhaust System

General Requirements ...................................................................23Muffler Selection .............................................................................23

Exhaust BackpressureExhaust Backpressure Calculations

Piping ..............................................................................................24Flexible Joints ..............................................................................25Water............................................................................................25

Rain CapOutlet BendDrain Holes

Converter/Mufflers ..........................................................................25Auxiliary Exhaust Brakes................................................................25Exhaust Pyrometers .......................................................................25

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GENERAL REQUIREMENTSIn order for an engine to produce its ratedhorsepower, attention should be given toexhaust gas flow restriction. Stringentlegislation requirements on vehicle noiselimits may require more restrictive exhaustsystems.

• When checked by Caterpillar’srecommended method, the exhaustbackpressure must not exceed the limitgiven on the Truck Engine Data Sheet.

• The exhaust piping must allow formovement and thermal expansion so thatundue stresses are not imposed on theturbocharger structure or exhaust manifold.

• Never allow the turbocharger to supportmore than 20 lb-ft (27 Nm).

MUFFLER SELECTIONThe muffler or silencer is generally the singleelement making the largest contribution toexhaust backpressure. The factors that governthe selection of a silencer include: availablespace, cost, sound attenuation required,allowable backpressure, exhaust flow, andappearance.

Silencer design is a highly specialized art.The silencer manufacturer must be givenresponsibility for the details of construction.For exhaust gas flow and temperatures, seethe Truck Engine Data Sheet.

Exhaust BackpressureBackpressure has an effect on the responseof an engine to load changes, exhausttemperatures, and fuel consumption. Exhaustsystems should be designed for about 25 in. ofwater to provide the best compromise betweennoise and backpressure. Sometimes thevehicle requirements may cause the designerto exceed 25 in. of water. Caterpillar Enginesare certified for smoke and gaseous emissionsunder Federal, California and other agencyregulations with backpressure up to thevalues listed in the Truck Engine Data Sheets.

• Exhaust stack temperatures increase about1.5°F for every 1 in. of water backpressure.

• The following examples show engineperformance changes from a muffler ratedat 25 in. of water at rated engine speed andload to one at 40 in. of water at rated speedand load:Engine 1

• 2100 rpm 325 hp1.3 hp decrease0.4% fuel consumption increase


Engine 2• 2100 rpm 425 hp

5.0 hp decrease1.2% fuel consumption increase








As a general rule of thumb, mufflermanufacturers indicate that fuel economy ofthe truck decreases an average of 0.5% per13.5 in. of water increase in backpressure.

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Exhaust Backpressure CalculationsSharp bends in the exhaust system willincrease exhaust backpressure significantly.The pipe adapter diameter at theturbocharger outlet is sized for an averageinstallation. This size decision assumes aminimum of short radius bends. If a numberof sharp bends are required, it may benecessary to increase the exhaust pipediameter. Since restriction varies inverselywith the fifth power of the pipe diameter, asmall increase in pipe size can cause anappreciable reduction in exhaust pressure.Since silencer restriction is related to inlet gasvelocity, in most cases a reduction in mufflerrestriction for a given degree of soundattenuation will require a larger silencer withlarger pipe connections.

It is essential that the system does not imposemore than the allowable maximumbackpressure. The maximum backpressurecan not be exceeded in certifying each enginemodel for conformity to exhaust smoke andexhaust gas emissions under Federal,California and other agency regulations.To avoid this problem, exhaust systembackpressure should be calculated beforefinalizing the design.

Estimation of the piping backpressure can bedone with this formula:

P = 0.22LQ2

D5 (460 +T)

Where:

P = Pressure drop (backpressure)measured in inches of water.

L = Total equivalent length of pipe in feet.

Q = Exhaust gas flow in cubic feet perminute at rated conditions.

D = Inside diameter of pipe in inches.

T = Exhaust temperature in °F.

Values of D5 for common pipe sizes are givenabove, top right:

To determine values of straight pipeequivalent length for smooth elbows use:

Standard 90° elbow = 33 x pipe diameterLong sweep 90° elbow = 20 x pipe diameterStandard 45° elbow = 15 x pipe diameter

To determine values of straight pipeequivalent length for flexible tubing use:

L = Lf x 2

Exhaust backpressure is measured as theengine is operating under rated conditions.Either a water manometer or a gaugemeasuring inches of water can be used. If notequipped, install a pressure tap on a straightlength of exhaust pipe. This tap should belocated as close as possible to the turbochargeror exhaust manifold on a naturally aspiratedengine, but at least 12 in. downstream of abend. If an uninterrupted straight length of atleast 18 in. is not available (12 in. precedingand 6 in. following the tap), take care to locatethe probe as close as possible to the neutralaxis of the exhaust gas flow. For example, ameasurement taken on the outside of a 90°bend at the pipe surface will be higher than asimilar measurement taken on the inside ofthe pipe bend. The pressure tap can be madeby using a 1/8 NPT half coupling welded orbrazed to the desired location on the exhaustpipe. After the coupling is attached, drill a.12 in. diameter hole through the exhaust pipewall. If possible, remove burrs on the inside ofthe pipe so that the gas flow is not disturbed.The gauge or gauge hose can then be attachedto the half coupling.

PIPINGWhen routing the exhaust system, considereach of the following factors:

Nominal ActualPipe Dia. ID D5

3.0 2.88 198.3.5 3.38 441.4.0 3.88 879.5.0 4.88 2768.6.0 5.88 7029.

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Flexible JointsFlexible joints are needed to isolate enginemovement and vibration and to offset pipingexpansion and contraction. From its coldstate, a steel pipe will expand .0076 in. per ftper 100°F temperature rise. For example, theexpansion of 10 ft of pipe with a temperaturerise of 50°F to 850°F is .61 in. If not accountedfor, the piping movement can exert unduestress on the turbocharger structure and thepipe supports.

The maximum allowable load that theturbocharger is permitted to support is 20 lb-ft (27 Nm). This usually requires thata support be located within four feet of theturbocharger, with a flexible connectionlocated between the turbocharger and thesupport. Manifolds for naturally aspiratedengines can support up to 50 lb.

Flexible joints should be located in alongitudinal run of pipe rather than on atransverse section. This allows flexibility forengine side motion.

WaterWater must not be permitted to enter theengine through the exhaust piping.

A low horizontal exhaust pipe mounting issometimes used, but it is difficult to find aplace under the chassis where the exhaust gascan be discharged without adversely affectingsome aspect of vehicle design. The tailpipeshould be tipped to the side and inboard toavoid noise bounce off the road and excessiveheat on the tires.

A vertical silencer mounting is more common.The exhaust outlet should be located so thatfumes do not enter the air cleaner or the cabunder any operating condition of the vehicle.Water protection for vertical systems caninvolve these items:

Rain Cap

Outlet BendA bend at the outlet is quite common. If it isthe sole method of excluding moisture, thebend should be a full 90 degrees, and theexhaust outlet directed towards the rear of

the vehicle. However, local laws should beconsidered since silencing effectiveness maybe altered.

Drain HolesDrain holes near a low point in the pipingare used. Holes smaller than 1/8 in. have atendency to become plugged, andunfortunately holes of that size or larger arelikely to be a source of noise and focus forcorrosion.

Consider installing a small drained expansionchamber in the piping.

CONVERTER/MUFFLERSAlthough a catalytic converter has beenrequired on some in engines in past years, acatalytic converter is not required on anytruck engines for certification in 1998.

AUXILIARY EXHAUST BRAKESCaterpillar concurs with the use of auxiliaryexhaust braking devices on the 3406, 3116,3126, 3126B and 3208 T Engines, with limitsas outlined in Section IVII Auxiliary BrakingDevices.

EXHAUST PYROMETERSWhile not offered by Caterpillar, an exhaustpipe thermocouple and related instrumentpanel mounted pyrometer is sometimesinstalled by the truck owner. Take care inmounting the thermocouple to not increasethe exhaust backpressure.

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Fuel System

Fuel .................................................................................................27General Requirements ...................................................................29

Inlet to Engine RestrictionReturn from Engine RestrictionFuel Line CompatibilityFuel Temperature

Fuel Tank Design............................................................................29Fuel Piping......................................................................................30Restriction Inlet to Engine...............................................................30Primary Fuel Filters.........................................................................30Fuel Pump Pressure.......................................................................30Fuel Line Size .................................................................................31Fuel Heaters ...................................................................................31Fuel Coolers....................................................................................32

General RequirementsDesign Criteria

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The fuel system supplied on Caterpillar TruckEngines is complete, and for most operatingconditions only the connecting supply andreturn lines are needed to make itoperational.

FUEL

Specifications

Distillate Diesel FuelDiesel fuels that meet the specifications inthe chart below will provide rated engineperformance and full component service life.In North America, diesel fuel identified asNo. 1-D and No. 2-D in ASTM D975 generallymeet these specifications. This chart is fordiesel fuels that are distilled from crude oil.Diesel fuels from other sources could exhibitdetrimental properties that are not defined orcontrolled by this specification.

There are many other diesel fuelspecifications published by governmentsand technical societies. Those diesel fuelspecifications usually do not contain all of theparameters addressed by Caterpillar in thisspecification. To assure optimum engineperformance, a complete fuel analysis shouldbe obtained prior to engine operation. The fuelanalysis should include all of the propertieslisted in the Distillate Fuel Recommendationschart. If a particular fuel does not meet theminimum Caterpillar requirements, theengine could exhibit excessive fuel systemwear, fuel system failure, or excessive enginewear caused by deposits or corrosion.

0.05 Percent Sulfur Diesel FuelIn the U.S.A., 0.05 percent sulfur diesel fuelhas been used in all on-highway diesel truckengines since January 1, 1994. This low sulfurfuel was mandated as a means of directlyreducing particulate emissions from dieseltruck engines. This low sulfur fuel will also beused in Caterpillar on-highway diesel truckengines where low emissions are required andwhere supply sources provide this type of fuel.Caterpillar has not seen any detrimentaleffects with 0.05 percent sulfur fuel inCaterpillar on-highway diesel truck engines.

NOTICE

Heavy Fuel Oil (HFO), Residual fuels, orBlended fuels must NOT be used inCaterpillar on-highway diesel truckengines. Severe component wear andcomponent failures will result if HFOtype fuels are used.

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SpecificationsRequirement

(ASTM Test Procedure)

Aromatics “D1319” 35 percent maximum

Ash “D482” 0.02 percent maximum

Carbon Residue on 10 percent Bottoms “D524” 1.05 percent weight maximum

Cetane Number “D613”35 minimum (for PC engines)40 minimum (for DI engines)

Cloud Point Maximum not above lowest expected ambient temperature

Copper Strip Corrosion “D130” No. 3 maximum

Distillation “D86”10 percent at 282°C (540°F) maximum90 percent at 360°C (680°F) maximum

Flash Point “D93” legal limit

API Gravity “D287” 30 minimum/45 maximum

Pour Point “D97” 6°C (10°F) minimum below ambient temperature

Sulfur “D3605” or “D1552”1 3 percent maximum1

Kinematic Viscosity at 40°C (104°F) 1.4 cSt minimum“D445”2 for additional information 20.0 cSt maximum

Water and Sediment “D1796” 0.1 percent maximum

Water 0.1 percent maximum

Sediment “D473” 0.05 percent maximum

Gums and Resins “D381” 10 mg/100 ml (5.8 grains/U.S. gal.) maximum

Lubricity by Scuffing Load Wear Test (SBOCLE)3100 g. minimum

or0.45 mm maximum at 60°C (140°F)

High Frequency Reciprocating Rig (HFRR)3 or0.38 mm maximum at 25°C (77°F)

Caterpillar Specifications for Distillate Fuel

1 Caterpillar fuel systems and engine components can operate on high sulfur fuels. However, fuel sulfur levels effect exhaust particulateemissions. High sulfur fuels increase the potential for internal component corrosion. Fuel sulfur levels above 1.0 percent may significantlyshorten the oil change interval. Refer to the TBN and Fuel Sulfur topic in the lubricant’s section for additional information.

2 The viscosity limits are for the fuel as delivered to the fuel injection pump. If low viscosity fuels such as JP-8, JP-5, Jet-A-1 or No. 1 diesel fuelare used, fuel cooling may be required to maintain a viscosity of 1.4 cSt at the fuel injection pump. Conversely, when using high viscosity fuelsor when operating in low temperature conditions, fuel heaters may be required to reduce viscosity to 20 cSt. Refer to Special Publication,SEBD0717, “Diesel Fuel and Your Engine”.

3 The lubricity of a fuel is a recent concern with the spread of low sulfur fuel. If the lubricity of a fuel does not meet the minimum requirements,consult your fuel’s supplier. Do not treat the fuel without consulting with the fuel supplier as some additives are not compatible and can causeproblems in the fuel system.

29

GENERAL REQUIREMENTSRequirements to be observed to obtain asatisfactory installation are as follows:

Inlet to Engine RestrictionThe flow restriction at the engine inlet mustnot exceed the value given on the TruckEngine Data Sheet for a particular engine.This restriction is based upon a fuel tank halffull of fuel. Total flow restriction limit includesany additional filtering devices added to thestandard Caterpillar engine.

Return from Engine RestrictionAll Caterpillar Truck Engines return fuelfrom the engine to the fuel tank(s). Thepurpose of this return fuel is to cool theinjectors and purge air from the system.Some OEMs offer optional shutoff valves inthe supply and return lines. There have beenreported cases where both return valves (dualsupply, dual return system) have been shutoff. Blockage of the return fuel has resulted inperformance problems and damage to the fuelsystem. Therefore, valves must not beinstalled in the fuel return line that can beshut and block the flow. On dual tank systemswith a dual supply, dual return a selector typevalve which would always allow fuel flow toone of the tanks is permissable.

All return systems must not exceed therestriction listed on the Truck Engine DataSheet for a particular engine.

Fuel Line CompatibilityFuel tank and fuel piping materials must becompatible with diesel fuel oil.

Fuel TemperatureThe fuel temperature must be withinacceptable limits as described in this section.

FUEL TANK DESIGNEither steel or aluminum is satisfactory as afuel tank material. Terneplate, phosphate, orplastic coatings are frequently used andrecommended for steel fuel tanks.

Fuel tanks should conform to requirements asdesignated by the Federal InterstateCommerce Commission and the Departmentof Transportation.

The end of the fuel pump suction line should belocated above the bottom of the tank to allowup to 5% of the volume for water and sediment.

Provide a drain valve to drain off the collectedwater or sediment.

The fuel return line connection should belocated so that return fuel and air is notdrawn in by the fuel supply tube. Separatingthe return and suction points by at least 12 in. in the horizontal plane is usuallysatisfactory. Baffling between these twoconnections is another way to increase theeffective horizontal distance between thesetwo points. For a vertical relationship, it isrecommended that the return outlet be abovethe maximum operating level of the fuel sothat entrained air is vented.

In addition to supply and return connections,the tank must be vented to allow forreplacement of fuel with air, as fuel isdelivered to the engine. The vent should bedesigned to minimize the ingestion of dustand dirt. This vent is subject to Federallegislation which should be consulted fordesign guidance.

Dual tank installations require an equalizerline. Equalizer line flow will be minimized ifthe fuel supply and the fuel return lines areconnected to the same tank.

Design of the filler neck and cap shouldconsider these items:

• Neck should extend above the tank tominimize inclusion of dirt and debris duringfilling.

• Use a removable screen of about .06 in.mesh to catch trash while filling.

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FUEL PIPINGFlexible hose is normally used for truckengine fuel piping. This hose should be a typespecified by the manufacturer as suitable forfuel oil. Currently acceptable material for theinner liner which is in contact with the fuelincludes Buna-N, Teflon*, nylon andneoprene. Low pressure hose suitable for a250 psi working pressure and capable of anoperating temperature range of 40°F to 200°Fis suitable. Observe minimum recommendedhose bend radii when routing the hose.

Steel tubing is acceptable providing sufficientlength of flexible hose is used to allow formovement between the truck chassis and theengine.

Copper tubing should not be used since ittends to work harden and crack at thefittings.

Tubing and hose should be clipped at regularintervals to prevent chafing. Avoid loops,either up or down.

Ensure inlet line connections are tight so thatair cannot enter fuel systems.

RESTRICTION – INLET TO ENGINERestriction to fuel flow is comprised of thefollowing elements: suction lift height of thefuel transfer pump above fuel tank, fuel lineand lifting frictional losses and primary fuelfilter restriction.

Variation in fuel tank mounting location forhighway trucks is not normally a problem.The fuel lift suction requirement to thetransfer pump height will normally beminimal.

Line restriction consists of both hose andfitting restriction. Fuel line length adds torestriction. Minimum practical line lengthsare recommended. Primary fuel filterrestriction will vary greatly due to typeand condition of the fuel filter.

*Trademark of DuPont

PRIMARY FUEL FILTERSFor all Caterpillar Truck Engines (3116, 3126, 3126B, 3306C DI, C-10, C-12,3406C, and 3406E), the use of a primary fuelfilter is required. The function of the primaryfuel filter is to protect the transfer pump andvalves from damage since these componentsprecede the engine mounted secondary fuelfilter.

For Caterpillar Truck Engines with a sleevemetering fuel system (3208 and 3306 PC), the use of a primary fuel filter is notrecommended. However, a fuel/waterseparator is required. The separator is afactory installed attachment on engines withsleeve metering fuel systems. On installationswhere the OEM provides the separator, itshould be installed between the fuel tank andthe engine fuel filter. A location should beselected that will provide space for routinemaintenance and visual inspection.

The flow restriction caused by the addition ofa primary fuel filter or water separator shouldnot raise the total inlet restriction above thelimit shown on the Truck Engine Data Sheet.Choice of a particular type of primary fuelfilter should be based on its intended function.The micron rating of the primary fuel filtershould not be so fine as to cause prematureplugging by contaminants or wax in coldweather conditions. A micron rating as coarseas 150 microns will provide adequateprotection for the transfer pump and primingpump.

Fuel oil may cause permanent damage toelectrical insulation. Therefore, care must betaken in the location of the primary fuel filter.If the fuel filter is located above the wiringharness or starter, a shield should be providedto protect this equipment during a filterchange.

FUEL PUMP PRESSUREThe use of a fuel pressure gauge visible to theoperator is recommended. It is commonlyinstalled in the instrument panel. Its chieffunction is to indicate a dirty and, therefore,restrictive fuel filter. The gauge is also useful

31

in indicating any malfunction of the fuelsystem causing loss of fuel pressure.

Nominal fuel pressure for the various enginemodels is shown on the Truck Engine DataSheet.

Engines (3306C and 3406C) with a pistontype fuel transfer pump require a snubber(Cat Part No. 7S3795) to damp out pulsationsinherent with this type of pump. The fuelpressure gauge is not a reliable indicator offlow restriction due to improper sizing ordesign of the fuel inlet system.

FUEL LINE SIZETo calculate fuel flow velocity in both thesupply and return lines, use the MaximumFuel Flow to Transfer Pump and Fuel ReturnLine Flow values given on the Truck EngineData Sheet.

Maximum recommended supply line andreturn line restriction is given on the TruckEngine Data Sheet. The supply line is definedas the pickup tube in the fuel tank and all ofthe hose or tubing which leads to andconnects onto the first standard or basic partof the truck engine.

The return line is simply the hose or tubingwhich connects the engine junction block orautomatic vent valve to the fuel tank. See theFuel System Schematic.

FUEL HEATERSWith mid-distillate No. 1 and No. 2 diesel fuel,cold weather can cause wax crystals to form infuel systems, partially or completely blockingfuel flow. The addition of a small amount ofheat to the fuel before it flows through thefilter(s) can prevent wax problems.

The fuel will flow through pumps and linesbut not through filters at temperatures belowthe cloud point. At temperatures below thepour point, the fuel will not flow in the lines orpumps. The use of fuel with a pour pointabove the ambient temperature is notrecommended. A fuel heater will often solve

cloud point problems. However, fuel heaterscannot solve pour point problems.

Following are several suggestions for applyingfuel heaters to Caterpillar Engines:

• Fuel heaters should be used when theambient temperature is below the fuel cloudpoint. Many types of heaters can be used;however, the fuel should be heated beforethe first filter in the fuel system. Fuelheaters should not be used when theambient temperature exceeds 60°F (15°C).Under no condition should the maximumfuel temperature at the outlet of the fuelheater exceed 175°F (79°C). However, whenthe outlet temperature exceeds 125°F (52°C), some power loss is to beexpected on some model engines.

• Heaters used should be capable of handlingthe maximum fuel flow of the engine. Therestriction created should not exceedpublished levels for the engine (publishedvalues for fuel flow and allowable restrictioncan be found on the Truck Engine DataSheet).

• For heaters using engine coolant as the heatsource, take coolant from taps in locationssimilar to those used for cab heaters.Normally there are sufficient taps provided.However, in vehicles which have severalexternal coolant loops for dual personnelheaters, block heaters, transmission coolers,etc., it may be necessary to connect the fuelheater into one of the other coolant loops. Ifthis is done, care must be taken to assurethat coolant shunting to one system does notadversely affect another system and thatboth have adequate flow.

• The electronic control module on someelectronically controlled engines is cooledby the fuel flowing to the engine. Fuel isnormally routed from the tank, to a primaryfuel filter, through the transfer pump, thenthrough cored passages in the electroniccontrol module, and on to the secondaryfilter, and finally to the injection pump. Inletfuel temperature to the transfer pump mustnever exceed 175°F (79°C). Fueltemperatures in excess of 175°F (79°C)reduce the life of the electronics and thetransfer pump check valves.

32

Fuel heaters used with electronicallycontrolled engines must be thermostaticallycontrolled or self-regulating. The fuel heatermay be self-regulating by design so its sizewill not allow it to overheat the fuel under theworst case conditions, i.e., 210°F (85°C) waterto the heater, low fuel flow, and 110°F (29°C) fuel to the heater. On truckswhere the cab temperature control on theheater regulates the water flow through theheater core, non-thermostatically controlledheaters may be made self-regulating byplumbing the fuel heater in series with theheater valve. The fuel heater should beplumbed upstream of the heater core for thefuel heater to be effective. This does notgenerally effect the heater output as there isonly about 3-4°F (2°C) drop in temperature ofthe water through the fuel heater.

When any fuel heater is used and ambienttemperatures are below approximately 32°F (0°C), the engine should be started andrun at low idle until the engine temperaturerises slightly. This allows heat transfer to thefuel before high fuel flow rates at high poweroutput are experienced by the system. Thiswill reduce the possibility of wax plugging thefuel filter shortly after a cold start.

Even with fuel heaters, operation of vehiclesis most difficult when the ambienttemperature is below the fuel pour point ofthe fuel. Thus operation with fuel that has apour point above the ambient temperature isnot recommended.

FUEL COOLERSThe C-10, C-12, and 3406E unit injectedengines bypass a large amount of fuel back tothe tank. Since this fuel passes through thecylinder head, the temperature of the returnfuel may be well above the limits establishedfor the fuel supply to the engine. Therefore,most single fuel tank installations will requirea fuel cooler in the return line and dual tankinstallations may require special routing ofthe return and supply lines to preventexcessively high fuel supply temperatures.

General RequirementsHigh temperature fuel to the fuel transferpump can result in a loss of performanceand/or reliability. The reliability of theelectronic control module, which is cooled bythe fuel supply, can be affected if the fuelsupply temperature exceeds 175°F for the C-10, C-12, and 3406E Engines. Thetemperature of the fuel flowing through theengine can increase approximately 60°F to70°F. Caterpillar requires the fuel supplytemperatures not exceed 175°F for the C-10,C-12, and 3406E Engines. To preventexcessively high fuel temperature in the fueltank from occurring under high ambientconditions (110°F normally) and low fuellevels, consider the following designs:

• Single TanksFuel cooler (design criteria below)

• Dual TanksFuel cooler and/or dual return and supplylines or return to one tank and supply fromthe other.

Other designs may also be effective. However,the design of the fuel system must be suchthat the fuel supply temperature does notexceed the temperature to transfer pump atall fuel levels in the tank(s).

Fuel Cooler Design Criteria

C-10 3406EC-12

Ambient Temperature - °F 110 110

Return Fuel Flow - gph 65 65

Return Fuel Temp (to cooler) - °F 210 220

Fuel to Tank Temp (from cooler) - °F 175 175

Heat Rejection Btu/min 119 154

Where ram air is used for the cooler, the sameram air velocity that is to qualify the radiator(normally 15 mph or 30 mph) should be usedin designing the cooler.

33

Lubrication System

Breathers ........................................................................................34Remote Mounted Oil Filters............................................................34Tilt Capability...................................................................................34Oil Level Gauge Marking................................................................34Bypass Oil Filters............................................................................35Engine Lubricant Specifications.....................................................35

General Information.....................................................................35Caterpillar Diesel Engine Oil ..........................................................35Commercial Diesel Engine Oils......................................................36Synthetic Base Stock Oils ..............................................................37Re-Refined Base Stock Oils...........................................................37Arctic Lubricants .............................................................................37After-Market Oil Additives...............................................................38Total Base Number and Fuel Sulfur Levels ...................................38Lubricant Viscosity..........................................................................38

34

Truck Engine Data Sheets for each engine giveoil system capacity, high and low oil sumplevels, normal oil pressure and oilspecification. Cold weather operation,as well as lube and filter change periodrecommendations, are covered in theCaterpillar Operations and MaintenanceManagement book for each engine.

BREATHERSCaterpillar diesel engines have crankcasebreathers that discharge into the atmospheresmall amounts of combustion gas whichpasses the piston rings and enters thecrankcase. Some midrange (3208) engines,however, have a positive crankcase ventilationvalve (PCV) which vents crankcase fumes intothe engine air inlet manifold. Thus, crankcasefumes are burned in the engine.

REMOTE MOUNTED OIL FILTERSSome heavy-duty diesel engines have thecapability for remote mounting of the oil filterwhen space limitation or serviceability is aproblem. However, authorization fromCaterpillar Inc. must be obtained beforemaking any modifications to the enginelubrication system.

When filters must be remote mounted, followthe following recommendations:

• Exercise cleanliness during removal andinstallation of oil filters and lines. Keep allopenings covered until final connections aremade.

• Use medium pressure, high temperature250°F (120°C) hose equivalent to orexceeding SAE 100R5 specification.

• Keep oil lines to within the minimum sizeand maximum length permitted. Consultfactory.

• Support hose as necessary to keep fromchafing or cutting on sharp corners.

• Use care in connecting oil lines so thedirection of oil flow is correct. Caution: Engine damage will occur if oilfilter is improperly connected.

TILT CAPABILITYInstallations at a permanent tilt or slantangle should be reviewed by Caterpillar Inc.to insure the lubrication system will functionproperly.

OIL LEVEL GAUGE MARKINGInstallations requiring a modified oil levelgauge should use the data in the TruckEngine Data Sheet to properly mark the oillevel gauge. The oil level gauge guide tubemust be vented to the crankcase at a pointabove the highest oil level to obtain accuratereadings. Check the gauge level markings,using the following recommended method.

• On the standard engine with no alterationswhich affect the engine, use the sumpcapacity.

• Service the engine with the low sumpcapacity shown in the Truck Engine DataSheet.

• Wait long enough for an equilibrium oil levelto be established.

• Make several readings to insure accuracy inchecking add oil– engine stopped level ongauge.

• Add the difference in oil capacity betweensump capacity high and low shown on theTruck Engine Data Sheets.

• Wait long enough for a new equilibrium oillevel to be established.

• Make several readings to insure accuracy inchecking full– engine stopped level on gauge.

35

BYPASS OIL FILTERSCaterpillar Truck Engines do not requiresupplemental bypass oil filter systems;however, such systems can be installed, ifrequested by user. When installed, thesesystems must have a non-drainback featurewhen the engine is shut down and a 0.125 in.maximum diameter orifice with 2 gpm (8 L/min) flow. Refer to the engine generaldimension drawings for the recommendedbypass filter supply location and oil return tothe crankcase.

Supplemental bypass filters which increasethe oil capacity may allow the oil, and in someengines the filter, change periods to beextended. Refer to the Caterpillar Operationand Maintenance Management book forrecommended change periods.

ENGINE LUBRICANT INFORMATION

General InformationApplicationBecause of government regulations regardingthe certification of engine exhaust emissions,the lubricant recommendations must befollowed.

API Licensed OilsCaterpillar recognizes and supports theAmerican Petroleum Institute (API) “EngineOil Licensing and Certification System” forengine oils. The API publication No. 1509,13th edition, contains the detailedinformation concerning this system. Engineoils bearing the API symbol are licensed bythe API.

Diesel engine oil classifications CD, CD-2, andCE are obsolete API categories. Caterpillarwill only reference those categories that arecurrently licensed by the API. The followingchart summarizes the status of the categories.

1 CD-2 and CF-2 are oil categories for two cycle diesel engines.Caterpillar does not sell engines that utilize CD-2 and CF-2category oils.

Note: CF is NOT the same as CF-4, API CFoils are only recommended for Caterpillarengines with precombustion chamber (PC)fuel system.

In previous lubricant specifications,Caterpillar referred to U.S. Military oilspecifications (MIL) and to European Comitedes Constructeurs d’Automobile MarcheCommun (CCMC) diesel engine oilspecifications. Those specifications do notprovide identical performance to API CF, CF-4or API CG-4 engine oils. Therefore,Caterpillar will not make reference to MIL orto CCMC specifications in this publication.

TerminologySome abbreviations follow the Society ofAutomotive Engineers (SAE) J754nomenclature. Some classifications follow theSAE J183 abbreviations. The definitions otherthan Caterpillar’s will be of assistance inselecting lubricants.

Caterpillar Diesel Engine Oil (DEO)Caterpillar Oils have been developed, tested,and approved by Caterpillar to provide theperformance and service life that has beendesigned and built into Caterpillar dieselengines. Caterpillar oils are used for enginedevelopment and factory fill. These oils areoffered by Caterpillar dealers.

Examples of the API symbol.

Current Obsolete

CF CC, CD

CF-21 CD-21

CF-4, CG-4 CE

Oil Classification Status

D41806

Due to significant variations in the qualityand in the performance of commerciallyavailable oils, Caterpillar recommends:

Caterpillar Diesel Engine Oil (DEO) 15W40Caterpillar Diesel Engine Oil (DEO) 10W30

Caterpillar recommends the use of multi-grade oils in all on-highway truck engines.

Caterpillar multi-grade DEO is formulatedwith detergents, dispersants, and sufficientalkalinity to provide superior performance inCaterpillar diesel truck engines. Multi-gradeDEO is blended in two viscosity grades:SAE 10W30 and SAE 15W40. Refer tothe Lubricant Viscosities For AmbientTemperatures chart to choose the correctviscosity grade based on ambienttemperatures. Multi-grade oils provide thecorrect viscosity for a broad range of operatingtemperatures and for cold engine starts.Multi-grade oils are also effective inmaintaining low oil consumption and lowlevels of piston deposits.

Caterpillar multi-grade DEO is also qualifiedfor use in other diesel engines and in gasolineengines. Refer to the engine manufacturer’sguide for the recommended specifications.Compare the recommendations to thespecifications of Caterpillar multi-grade DEO.The current Caterpillar multi-grade DEOindustry specifications are listed on theproduct labels and on the product data sheets.

Contact your Caterpillar dealer for partnumbers and available container sizes.

Commercial Diesel Engine OilsThe performance of commercial diesel engineoils is based on API categories. API categoriesare developed to provide commerciallubricants for a wide variety of diesel enginesthat operate in various conditions.

If Caterpillar multi-grade DEO is not used,the following commercial oils arerecommended.

• Preferred API CG-4 (multi-grade)• Acceptable API CF-4 (multi-grade)

API CG-4 oils are preferred for Caterpillar on-highway diesel truck engines because the oilsprovide improved deposit control andadditional soot dispersancy. Also, API CG-4 isthe only oil category that evaluates oils withengine tests utilizing 0.05 percent sulfurdiesel fuel. Since October 1, 1993, all U.S.A.on-highway truck diesel fuel has beenregulated to a maximum of 0.05 percentsulfur.

The following explanations of these APIcategories can be used to make the properchoice of a commercial oil.

CG-4: CG-4 is the newest heavy duty dieseloil category. CG-4 oils can be used in allCaterpillar on-highway diesel truck engineswhere CF-4 oils are recommended. Comparedto CF-4 oils, CG-4 oils provide improvedpiston cleanliness, improved viscosity control,and improved crankcase cleanliness,especially in applications where oil soot is aproblem. Although CG-4 oils were primarilydeveloped for diesel engines operating on 0.05percent sulfur diesel fuel, CG-4 oils can beused with higher sulfur fuels. The new oilTBN determines the maximum fuel sulfurlevel for CG-4 and CF-4 oils. Refer to the TBNand Fuel Sulfur topics in this publication.

CG-4 oils are the first oils to pass industrytests for foam control and viscosity shear loss.CG-4 oils must also pass recently developedtests for metals corrosion and wear.

CF-4: CF-4 oils service a wide variety ofmodern diesel engines. This oil classificationwas developed with 0.40 percent sulfur dieselfuel. The fuel used in the CF-4 categoryrepresents the type of diesel fuels commonlyavailable worldwide. CF-4 oils provideimproved piston deposit control andimproved oil control when compared to the CE category oils. CF-4 oils also provideimproved oil soot dispersancy compared to CD or CF category oils.

Note: Single grade or multi-grade CF oils arenot recommended for current Caterpillar on-highway diesel truck engines.

36

37

Some commercial oils meeting these APIspecifications may require shortened oilchange intervals as determined by closemonitoring of oil condition and wear metals(Caterpillar’s S•O•S Oil Analysis Programpreferred).

NOTICE

Failure to follow these oil recommenda-tions can cause shortened engine servicelife due to deposits and/or excessivewear.

NOTICE

Single grade Oils must not be used inCaterpillar on-highway diesel truckengines, regardless of the API speci-fication.

Synthetic Base Stock OilsSynthetic base stock oils are acceptable foruse in Caterpillar engines if these oils meetthe performance requirements specified byCaterpillar.

Synthetic base stock oils generally outperformnon-synthetic oils in two areas:• Improved low temperature viscosity

characteristics, especially in Arcticconditions

• Improved oxidation stability, especially athigh operating temperatures.

Some synthetic base stock oils haveperformance characteristics that enhance theuseful service life of the oil. However,Caterpillar does NOT recommend the“automatic” extension of oil change intervalsfor any oil, including synthetic base stock oils.For Caterpillar diesel engines, oil changeintervals can only be adjusted through an oilanalysis program that contains the followingelements: oil condition and wear metals(Caterpillar’s S•O•S Oil Analysis preferred),trend analysis, fuel consumption, and oilconsumption.

Re-Refined Base Stock OilsRe-refined base stock oils are acceptable foruse in Caterpillar engines if these oils meetthe performance requirements specified byCaterpillar. Re-refined oils can be usedexclusively in a finished oil or in combinationwith new base stocks. The U.S. Military andother heavy equipment manufacturers havealso accepted the use of re-refined base stockoils with the same criteria.

The re-refining process should be adequate toremove all wear metals and oil additives thatwere present in the used oil. This type of re-refining is generally accomplished by vacuumdistillation and hydrotreating the used oil.Filtering alone is inadequate for producing ahigh quality re-refined base stock from usedoil.

Arctic LubricantsFor starting and operating engines in ambienttemperatures below –20°C (–4°F), use a multi-grade oil with a 0W or 5W low temperatureviscosity grade.

For starting and operating engines withambient temperatures below –30°C (–22°F),use a synthetic base stock multi-grade oil witha 0W or 5W low temperature viscosity gradeand a pour point of –50°C (–58°F) or lower.

Because the number of lubricants acceptablefor use in Arctic conditions is limited,Caterpillar has special recommendations forthese situations. Caterpillar recommends thefollowing engine oils, in order of preference,for use in Arctic conditions:• First Choice: API CG-4 or CF-4 oils with an

SAE 0W20, 0W30, 5W30, or 5W40 viscositygrade

• Second Choice: Oils with a CG-4 or CF-4type additive package and an SAE 0W20,0W30, 5W30, or 5W40 viscosity grade.

NOTICE

Shortened engine service life couldresult if second choice oils are used.

38

After-Market Oil AdditivesCaterpillar does NOT recommend the use ofafter-market oil additives. After-market oiladditives are not necessary to achieve servicelife predictions or to achieve ratedperformance. Fully formulated finished oilsare made up of base stocks and commercialadditive packages. The additive packages areblended into the base stocks at precisepercentages to produce finished oils withperformance characteristics that meetlubricant industry standards.

Lubricant industry standard tests do not existto evaluate the performance of after-marketoil additives. There are no lubricant industrystandard tests to evaluate the compatibility ofafter-market additives in a finished oil. After-market additives could be incompatible withthe finished oil additive package, reducing theperformance of the finished oil. The after-market additives could fail to mix with thefinished oil, producing a sludge in thecrankcase. Caterpillar discourages the use ofafter-market additives in finished oils.

Total Base Number (TBN) and FuelSulfur Levels For Caterpillar DIDiesel EnginesThe TBN required in a new oil depends on thesulfur level of the fuel used. For directinjection engines running on distillate dieselfuel, the minimum new oil TBN (by ASTMD2896) should be 10 times the fuel sulfurlevel, and the minimum TBN is 5 regardlessof a low fuel sulfur level—refer to thefollowing graph.

Y = oil TBN shown by ASTM D2896.X = percent of fuel sulfur by weight.New oil TBN (1).Change oil when the used oil TBN limit (2) is reached.

In areas where the fuel sulfur exceeds 1.5percent, choose an oil with the highest TBNthat is within the API CF-4 or CG-4categories, and shorten the oil change intervalbased on oil analysis. The oil analysis shouldevaluate oil condition and wear metals. HighTBN oils that are not within the API CF-4 orCG-4 categories can produce excessive pistondeposits, leading to a loss of oil control andbore polishing.

NOTICE

Operating with fuel sulfur levels over 1.0percent may require shortened oilchange intervals in order to maintainadequate wear protection.

Lubricant ViscosityThe proper SAE viscosity grade oil isdetermined by the minimum outsidetemperature at cold engine start up, and themaximum outside temperature during engineoperation. Use the minimum temperaturecolumn on the chart to determine the oilviscosity required for starting a “cold soaked”engine. Use the maximum temperaturecolumn on the chart to select the viscosity foroperation at the highest temperatureanticipated. In general, use the highestviscosity oil available that still meets the startup temperature requirements.

Caterpillar DEO Ambient Temperature

API CG-4 & CF-4 Minimum MaximumViscosity Grade °C (°F) °C (°F)

SAE 0W20 –40 (–40) 10 (50)

SAE 5W30 –30 (–22) 30 (86)

SAE 5W40 –30 (–22) 40 (104)

SAE 10W30 –20 (–4) 40 (104)

SAE 15W40 –15 (–5) 50 (122)

Engine Oil Viscosity Protection

39

Cooling System

System Description.........................................................................42Shunt System ..............................................................................42Coolant Pump..............................................................................43Temperature Regulator................................................................43Vent Line ......................................................................................43

General Requirements ...................................................................43Cooling Capability........................................................................43

Maximum Top Tank TemperatureRecommended Ambient Capability

Filling Ability Recommended Ambient Capability .......................44Filling Ability ..............................................................................44

Pump CavitationDrawdownAir Venting Ability (Deaeration)

Cooling Parameters and Performance Tests.................................46Introduction ..................................................................................46Description of Tests and Definition of Terms...............................46

Cooling CapabilityFilling CapabilityPump Cavitation TemperatureDrawdownAir Venting Ability

Preparation and Instrumentation.................................................47Water System TestsAmbient Temperature Test

Procedure ....................................................................................47Filling Tests................................................................................47

Bucket MethodHose Method

Water System Tests..................................................................48Cavitation TemperatureDrawdownAir VentingPlotting Data

Ambient Capability Tests ..........................................................50Data RequiredAmbient Capability Determination

Fuel RateAmbient

40

Air ConditionerHead WindAltitudeAdditional CoresAmbient Capability

BrakeSaver Equipped Engines (3406E)Review Information......................................................................51

The Cooling System .......................................................................52Plumbing ......................................................................................52Radiator Vertical Flow.................................................................52

Top Tank....................................................................................52Radiator InletBaffle DesignShunt Line ConnectionBaffle Vent TubeEngine Vent ConnectionLow LevelLow Level Indicators

Metal PlateSight WindowDownward Extension of the Filler PipeLow Level Alarm

Bottom Tank ..............................................................................53Outlet PipeDrainsHeight

Radiator Horizontal Flow ............................................................54Radiator Core...............................................................................54Radiator Filler Cap.......................................................................54Radiator Mounting .......................................................................55Transmission and Retarder Oil Coolers......................................55Fan Recommendations ..............................................................55

Diameter and Speed.................................................................55Selection....................................................................................56

AirflowSensitivity

Fan Laws...................................................................................56Fan Shrouds and Fan Locations.................................................56Air Flow Losses and Efficiency....................................................56

ObstructionsAir Recirculation BafflesBlower Fans

41

Fan Drive......................................................................................57Overhanging Moment

Temperature Control....................................................................58Minimum TemperatureShuttersShutterstat SettingsThermatic Fan DriveShutterless Operation

Gauges and Devices ...................................................................58Water Temperature GaugesWarning and Shutdown DevicesCoolant Heaters

Coolant Connections ...................................................................59Pump DischargeAfter Engine Oil CoolerTop of EnginePump InletAdditional Cooling System ConnectionsEngine VentLocation of Coolant Connections

Coolant Information .....................................................................60WaterAdditivesGlycolCoolant RecommendationsExtended Life Coolant (ELC)Extended Life Coolant (ELC) Cooling System MaintenanceDiesel Engine Antifreeze Coolant (DEAC)Supplemental Coolant Additive (SCA)Conventional Coolant/Antifreeze Cooling System Maintenance

42

SYSTEM DESCRIPTION

Shunt SystemA shunt cooling system (Figure 4) isrecommended for all Caterpillar TruckEngines. This cooling system helps preventpump cavitation by maintaining a positivepressure head of coolant at the pump inlet atall times. The radiator top tank is divided intotwo compartments (upper and lower) with asmall air/coolant bleed or baffle vent tubeconnecting them. The upper compartmentmay be a remote mounted tank. A shunt linelocated as low as possible in the upperchamber directs coolant to the pump inlet.When the coolant reaches the temperature

required to open the temperature regulator,coolant is directed to the lower chamber of theradiator top tank, down through the radiatorcore to the suction line of the pump and thento the engine. Coolant, which may containsome air, tends to flow from the lowerchamber to the top chamber through thesmall air/coolant tube. The air separates fromthe coolant in the upper chamber. Thedeaerated coolant will flow down the shuntline and the separated air remains in theupper chamber until excessive pressure isbuilt up, at which time it will vent outthrough the pressurized radiator cap.

Figure 4

TemperatureRegulator

(Partially Open)Engine Vent

Baffle Vent

Upper Chamber

Baffle

Shunt Cooling System

Radiator

Lower Chamber

43

Coolant PumpDepending on engine model, the centrifugal-type pump is gear or belt driven. On typicalengines, the pump discharge is directedthrough the engine oil cooler and thenthrough the engine. See the Truck EngineData Sheet for coolant pump performancedata.

Temperature RegulatorModulating temperature regulators(thermostats) are standard on all CaterpillarTruck Engines rather than a chokethermostat. When the temperature regulatorsare closed, the coolant is recirculated in theengine through the coolant bypass line (orpassage). Since the bypass flow is relativelyunrestricted until the temperature regulatorsopen and shut off the bypass completely, thecooling system is known as a full-flow bypasscooling system. See the Truck Engine DataSheet for regulator start to open and fullyopen temperatures. Some engine models mayoffer a dual regulator option which will resultin high coolant flow rates due to lessrestriction. Dual regulators should beconsidered for hard to cool applications.

Caution: Never operate an engine withouttemperature regulators installed.

Vent LineExcept for the 3208, 3116, 3126, and 3126BEngines, an engine vent connection is

required at one end of the top tank above thecoolant level to bleed air trapped in theengine during filling. This vent line should beconnected to a point indicated on the EngineGeneral Dimension Drawing (Item 131). Thisconnection is on the engine side of thetemperature regulator(s) and should beorificed to .19 in. (4.8 mm) I.D. Some engineshave a factory installed orifice. Consultfactory for availability. The use of a vent linemay be needed on 3116, 3126, and 3126B tomeet filling requirements.

GENERAL REQUIREMENTSA properly functioning engine cooling systemis essential to satisfactory engine and vehiclelife, as well as performance. To achievesatisfactory engine life, Caterpillarrecommends or requires that the coolingsystem meet minimum standards of theseparameters:

Cooling CapabilityCaterpillar requires that top tanktemperatures not exceed the limits shown onthe Truck Engine Data Sheet. Mount a highcoolant temperature warning device set 5°Fabove the maximum top tank temperaturebetween the cylinder head and waterregulator. Refer to the Engine GeneralDimension Drawing for specific location.Electronically controlled engines may alreadyprovide the temperature warning function.

Ambient capability (or cooling capability) isthe ambient temperature that produces themaximum allowable top tank temperatureunder certain specified test conditions usingwater as the coolant. Although water isrecommended for testing because it providesmore consistent results, 50/50 water/glycolmixture may be used for testing. If 50/50water/glycol mixture is used for ambienttesting, the recommended ambient capabilityshould be lowered 6°F (3°C). The percentwater/glycol in the engine should bemeasured and recorded. Cooling system tests(cavitation, drawdown, etc.) must always bedone with water only. The following tablegives the recommended level of ambientcapability for various parts of the world. Thegeographical locations covered by the variouslevels are shown in the table on page 45. Theminimum ambient temperature for testing todetermine the ambient capability is also listedbelow. The maximum ambient temperaturefor testing is when the top tank reaches themaximum allowable top tank temperature.

Since the engine manufacturer does not knowall of the factors involving the application, itis the installer’s responsibility to know thespecific application and provide higherambient capability, if required.

Filling AbilityThe cooling system must be capable of asustained fill (hose) rate of 5 gpm (19 L/min).

The system must tolerate an interrupted(bucket) type fill without air lock (false fill).

Pump CavitationProvide sufficient head to the water pump sothat cavitation (specified reduction of pumppressure rise) does not occur until the pumpcavitation temperature shown in the TruckEngine Data Sheet is reached.

DrawdownThe cooling system must meet the drawdownrequirements given in the Truck Engine DataSheet.

Air Venting Ability (Deaeration)The radiator must have air/water separationcapabilities at least equal to the introducedair and pump pressure rise loss values givenin the Truck Engine Data Sheet.

44

A

B

C

D

15/24

15/24

15/24 (1)

15/24

90/32.2

100/37.8

110/43.3

122/50.0

80/26.6

90/32.2

100/37.8

112/44.4

55/12.8

55/12.8

55/12.8

65/18.3

MinimumAllowable Ambient

LevelRam Air

Velocity (1)mph/km/hr

Evaluation or Rated rpm°F/°C

Peak Torque +100 rpm°F/°C

Test Conditions°F/°C

MinimumAmbient Capability

(1) The 475 hp and above 3406E ratings are allowed 30 mph (48 km/h) for all on-highway applications.

For engines with a peak torque of 1650 lb-ft for greater, 30 mph (48 km/h) is allowed whenall of the following conditions exist:• On-highway Only

• 80,000 lb Maximum GCW

• U.S.A. Operation

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USA ............................CUSA _ Alaska ............B

Canada.......................BGreenland ..................A

Mexico ........................CCentral America........B

West Indies ................B

Europe

Caterpillar Recommended Ambient CapabilityTrucks

Aden ...........................CAfghanistan...............DBrunei ........................BBurma ........................CCambodia...................CCeylon ........................CChina..........................CIndia...........................DIndonesia ...................B

Iran.............................DIraq.............................DIsrael ..........................DJammu/Kashmir .......CJapan..........................BJordan........................DKorea..........................BKuwait .......................DLaos ............................C

Lebanon .....................DMalaya, Fed...............BMongolia ....................BNepal ..........................CNew Zealand..............BNorth Bornea.............BOmar & Muscat ........DPakistan.....................DPhilippine Islands.....B

Saudi Arabia .............DSarawak.....................BSyria...........................DTaiwan........................BThailand.....................CTrucial Kingdom .......DTurkey ........................CVietnam......................CYemen.........................D

Asia

North America

Argentina...................CBolivia ........................CBrazil..........................CChile ...........................B

Colombia ....................BEcuador......................BFrench Guiana ..........B

Guyana.......................BParaguay....................CPeru............................B

Suriname ...................BUruguay.....................CVenezuela...................B

South America

Algeria .........................DAngola ..........................CBotswana .....................CBurundi........................CCameroon.....................CCentral African Rep....CChad.............................DRepublic of Congo .......CEquatorial Guinea ......CEthiopia .......................DGabon...........................CGambia ........................D

Gahana ........................CGuinea..........................CGuinea-Bissau.............CIvory Coast ..................CKenya...........................CLesotho.........................CLiberia..........................CLibya ............................DMadagascar .................CMalawi .........................CMali ..............................D

Mauritania ..................DMorocco........................DMozambique................DNamimbia....................CNiger ............................DNigeria .........................CRwanda........................CSenegal ........................DSierra Leons ................CSomalia........................DRep. of South Africa....C

Sudan...........................DSwaziland ....................CTanzania ......................CTogo ..............................CTunisia .........................DUganda.........................CUnited Arab Rep.........DUpper Volta .................DZaire .............................CZambia .........................CZimbabwe ....................C

Africa

Antartica A Australia C*

Albania.......................CAndorra......................CAustria .......................BBelgium......................BBulgaria .....................CCyprus........................DCzechoslovakia..........BDenmark....................AFinland.......................A

France ........................CEast Germany ...........BWest Germany...........BGibraltar ....................CGreece ........................CHungary.....................BIceland........................AIreland........................AItaly ............................C

Liechtenstein.............BLuxembourg ..............BMalta..........................CMonaco.......................BNetherlands...............BNorway.......................APoland ........................BPortugal .....................CRumania ....................B

San Marino................CSpain ..........................CSweden.......................ASwitzerland................BTurkey ........................CUnited Kingdom........ACIS (formerly USSR) ..BSerbia, Montenagro(formerly Yugoslavia) ...C

*Except off-highway, on/off-highway, and road train applications should be level D.

46

COOLING PARAMETERS ANDPERFORMANCE TESTS

IntroductionThe cooling system must be designed toadequately cool the engine across the entirespeed and load range. The preliminary designis based upon many variables andassumptions. For this reason the coolingsystem for a particular engine installationmust be confirmed by actual test. Caterpillarengineers will at times conduct the test series.

Performance limits are listed separately. Theycan be found on the Truck Engine Data Sheet.

Description of Tests and Definition of TermsCooling CapabilityCooling capability (or ambient capability) isthe ambient temperature that produces themaximum allowable top tank temperature (asfound on the Truck Engine Data Sheet) undercertain specific test conditions. Ambient testsare run with the air conditioner operating, ifthe vehicle is so equipped. For ambient test100% water is recommended as a coolant asit produces more consistent results.

Filling AbilityFilling ability is the ability to fill the coolingsystem at a five gallon per minute sustainedrate. If filling is interrupted during someportion of the fill cycle due to an air locka false fill can result.

The coolant level, after initial fill procedurehas been followed, should not drop below thelow water level after the engine has beenoperated. (See drawdown for definition of low level.)

Pump Cavitation TemperaturePump cavitation temperature is the watertemperature at the pump inlet when thepermissible reduction in pump pressure riseis reached. Pump cavitation temperaturemust be equal to or greater than the highestwater temperature expected at the pump inletunder rated load, based upon a 210°F (99°C)engine water outlet temperature. Theminimum cavitation temperature allowed isshown on the Truck Engine Data Sheet.

Pump pressure rise is the pressuredifferential between pump outlet and pumpinlet expressed in feet of water (typically thiswill be from 35 to 50 ft (9.15 to 15.25 m) ofwater. The reference pump rise for all tests isdetermined with the coolant systemcompletely full at 120°F (48.4°C) and enginerunning at governed speed (2100 rpm for C-10, C-12, 3406E).

DrawdownDrawdown is the tendency for pump rise to belost as the coolant level is reduced to andbelow the low level indicator. In the absenceof a low level indicator, the defined low level is 9% for the 3116, 3126B and 3208 Enginesand 12% for heavy-duty engines of the totalsystem volume down from brimful. The loss inpump rise at the low level with 180°F (81.4°C)coolant cannot be greater than 10%.

Air Venting AbilityAir venting ability (deaeration) is the radiatorgas/water separating capability. It measuresthe rate of entrained air removal from thecooling system under controlled testconditions. Entrained air may be caused bycombustion gas leakage into the coolant.Venting ability is an air volume equal to 5% ofengine displacement per minute at 35% pumprise loss.

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Preparation and InstrumentationFor the water system tests, obtain the following equipment• An engine speed pickup and appropriate

readout device.• Thermocouple at the water pump outlet and

engine outlet (or top tank) and appropriatetemperature readout.

• A precision differential gauge betweenpump outlet and pump inlet. 30 psi(2.1 kg/cm2) (70 ft. {21.35m} H2O) capacity.

• A combination pressure/vacuum gauge onthe pump inlet. 5 psi (0.35 kg/cm2) (11 ft {3.35 m} (H20) capacity.

• A metering valve and pressure regulator forinjecting air into the engine block during theventing test.

• A vented radiator cap for the venting test.• A small container (L, qt or pt), a radiator fill

bucket, and an open mouth bucket or tubsuitable for immersion of the smallcontainer for the air venting test.

• A stopwatch.• Thermostats blocked open .38 in. (9.5 mm)

for the cavitation, drawdown, and airventing tests. Puncture the power pill toprevent further opening.

• A water hose for the hose filling test.• Cardboard (enough to block radiator

airflow).• Engine speed control device for adjusting

and maintaining engine speed.

For the ambient capability test, obtain the following equipment• An engine speed pickup and readout device.• Thermocouples, connected to an appropriate

readout device, at the following locations:Engine outlet (or top tank).Pump inlet (or bottom tank).Engine oil gallery (to bearings).Air to core (average set of 6-10).One of three remote ambient locations.Engine air inlet.

• A governor continuity light (mechanicallygoverned engines only).

• A fuel rate measuring device (flowmeters,if no scales are available).

• Gauges for boost, inlet restriction, andexhaust backpressure. Boost gauge capacity30 psi (2.1 kg/cm2) (70 in. {1.78m} Hg)capacity.

• Thermostats blocked open .38 in. (9.5 mm)with the power pill punctured to preventany further opening.

ProcedureThis procedure is set up so that each testfollows logically. However, it is not necessarythat this sequence be followed.

Filling TestsCompletely drain the cooling system {radiator,engine block, heater circuit(s)} before eachfilling test. Operational thermostats are used.The system volume can be determined duringthe bucket method by recording the amount ofcoolant used. The cab heater circuit(s) shouldbe open.

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Bucket MethodUsing an available fill bucket (10-12L sizeworks best) pour contents into cooling systemfill neck as quickly as possible. Allow this tosettle, then repeat until reaching brimful,allowing the water level to come to restbetween each bucket full. Record the volumeof water poured into the system as initial fillvolume.

While monitoring pump rise, start the engineand allow to idle a couple of minutes, thengradually increase engine speed. If pump risefalls off, or fails to rise with engine speed,return to idle for a few more minutes to see ifthe trapped air will purge itself. If it does not,the system may need modification to preventpump air lock.

If pump rise appears normal, install loosefitting radiator cap (to prevent over-spills)and run engine at rated speed or high idleuntil the thermostats have opened. Thengradually reduce speed to idle, let watertemperature return to 175-180°F (80-82°C),and stop engine. Measure the amount ofwater needed to bring the system back tobrimful. This is the bucket fill makeupvolume which must be less than 12% (9% for the 3208, 3116, 3126, and 3126B)of the total system volume to be acceptable.

The total system volume can be determined.The initial fill volume expands by 2% whenthe temperature is raised to 180°F (82°C) toopen the thermostat(s). Therefore, the totalsystem’s volume = initial fill volume x 1.02 +makeup volume.

Hose MethodFill the system at a constant 5 gpm (19Lpm)rate. Measure the amount of time frominitiating the fill until the filler neckoverflows. Recheck the hose flow rate afterthe fill to verify the rate has not changed.Start the engine as in the bucket method toascertain the pump does not air lock and todetermine the hose-fill makeup volume.Subtract the makeup volume from thepreviously determined total system volumeand divide this number by the time measuredto hose fill. This is the hose-fill rate (gpm).The hose-fill makeup volume must be lessthan 12% (9% 3208, 3116, 3126, and 3126B)

of the total system volume to be acceptable.

Water System TestUse thermostats which are blocked open .38 in. (9.5 mm) with the power pill puncturedto prevent any movement of the thermostat.Tests are run without a pressure cap and atgoverned speed (2100 rpm for C-10, C-12,3406E). Monitor the engine outlettemperature to avoid exceeding 210°F (99°C).Record the temperature at which watertemperature warning devices are activated,and also when thermostatically controlledshutters or fan operate, if the installation isso equipped and they set to activate below210°F (99°C). If water pump is belt driven(3208, 3116, 3126, and 3126B), check belts forproper tension.

Cavitation TemperatureFill the cooling system with cold water. Startthe engine and idle to purge the system of air,and then fill the system completely to brimful.With the engine at governed speed (2100 rpmfor C-10, C-12, 3406E) (no load, if possible)measure pump outlet temperature, pumpinlet pressure, and pump pressure rise.Gradually raise the water temperature byblocking radiator airflow. Record the pumprise and pump inlet pressure at 120°F (49°C).Record data at 10°F (5°C) intervals from120°F to 180°F (50°C to 80°C) and atincreasingly smaller intervals as the pumprise begins to decrease. Continue untilreading 210°F (99°C) engine outlettemperature or until pump rise has dropped15% below the reference value. Record thetest site barometric pressure (not corrected tosea level) prior to, during, or after completingthe cavitation test. If it is necessary to obtainthe barometer reading from a local airport orweather service, it will be corrected to sealevel. Find out the test site elevation andsubtract 1 in. Hg per 1000 ft (11 mbar per100 m) above sea level from the correctedbarometer to obtain the actual test sitebarometer reading. When tabulated, correctthe cavitation temperature to a standardbarometer reading of 29.60 in. Hg. (Add 1°Fto the measured cavitation temperature foreach 0.5 in. Hg barometer reading below29.60 in. Hg; reverse this procedure ifbarometer is above 29.60.

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DrawdownAllow the jacket water to cool to 180 ± 2°F (82 ± 1°C) at the pump outlet, maintaininggoverned speed (2100 rpm for C-10, C-12,3406E), and adding water to return thesystem to brimful. Record pump outlettemperature, pump inlet pressure and pumppressure rise. Holding temperature constant,drain water from the high pressure side of thepump (or block drain) in suitable increments(L or qt. for most installations) recording databetween each. As pump rise starts to fall off,reduce increments, continuing until thespecified volume above the low level has beenremoved and/or pump rise has dropped 15%below the reference value.

Air VentingMaintaining governed speed (2100 rpm for C-10, C-12, 3406E) and 180 ± 2°F (82 ± 1°C)pump outlet temperature, restore the waterlevel to a qualified low mark, and install the

special vented radiator cap. Inject pressurizedair into the engine block jacket waterdownstream of the water pump and oil cooler(usually the block drain). Start with a lowrate and gradually increase, recording pumppressure rise at each air venting rate.Measure the air vented from the system byobserving the time to displace water from aknown volume container inverted in a bucketor tub of water. Allow at least 3 minutesbetween changing rate of air injection andrecording data so that the system canstabilize. Terminate the test when the ventingrate is well in excess of the requirement orwhen pump rise dropped below 50 percent ofthe reference value.

Plotting DataIn addition to tabulated results, plot curvesof cavitation, drawdown and venting asillustrated in Figure 5. Plot these curvesusing a common pump pressure scale.

Truck Cooling System Test Data

Figure 5

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Ambient Capability TestUse blocked open thermostat(s) as for thewater system tests. Fill the cooling systemto the full mark (bottom of filler neck) withwater and install an operative cap. Check fandrive belts for proper adjustment to minimizeslippage. Check throttle linkage to assure fullmovement of the governor control lever at theengine (mechanically governed engines only).

On-highway trucks are tested at full throttle(maximum speed governor control position)and loaded to evaluation speed (shown on theTruck Engine Data Sheet) (+0, -50 rpm), at apeak torque +100 rpm (±25 rpm), 100 rpmabove the lowest downshift shift speed ifautomatic transmission equipped, and 80%torque converter efficiency, if equipped.

Engine loading can be accomplished byvarious means, depending on the installationand the equipment available at the test site.On-highway trucks can be operated on achassis dynamometer, or loaded by a chassismounted dynamometer connected to the driveshaft, or even operated up a long hill with asuitable drag load, (towing dyno).

A field test may be most useful in evaluatingthe ambient capability of some installations.Whichever method is used for the test, if theunit is equipped with a radiator mounted airconditioner condenser core, operate the airconditioner at maximum capacity duringthe test.

Also for all tests, if possible, measure therated fuel usage with supply fuel temperature125°F (52°C). If the measured fuel rate variesmore than 5% from the nominal fuel rate,recheck the governor control linkage(mechanically governed engines only) andcheck to see that neither the fuel supply northe air inlet is restricted. If no obviousproblem is found, it may be necessary to resetthe engine fuel setting.

Once engine performance has been verified,begin the ambient capability test. If theambient test is conducted indoors, minimizeair recirculation due to test cell effects andhot spots where possible by moving air pastthe installation. A 15 mph (24 km/hr) or 30 mph (48 km/hr) (as appropriate for theapplication, see Cooling Capability) headwind should be provided for on-highway

trucks. If the test facility is not capable ofproviding air movement, engineeringjudgment must be used in thermocoupleplacement and in determining cell-related vsinstallation-related recirculation effects. If thefacility has ambient control, maintain airtemperature above 90°F (32°C). Ambient airtemperatures below 55°F (12.8°C) are notrecommended.

Data Required• Engine speed• Output power (if measurable)• Fuel rate• Top tank (engine outlet) temperature• Bottom tank (pump inlet) temperature• Engine oil to bearing temperature• Ambient temperature• Air to core temperature (avg. 6 to 10)• Inlet air to engine temperatureAnd when possible:• Inlet manifold pressure (boost)

Record data when operating conditions havestabilized. Stabilized conditions exist whenengine speed and load have remainedconstant (within reason) for at least 15 minutes, and the differential (top tankminus ambient) temperature does not changebetween consecutive sets of readings obtainedwithin a 5 minute interval.

If the measured air to core temperature issignificantly higher than ambient, determine(by feel) if obvious air recirculation existsaround the radiator. It may be necessary toimprove baffling around the radiator to keepair to core temperatures as close to ambientas possible. Test the ambient capability of theunit in the as built configuration first, anddocument those results. Then determine whatgains can be made with improved baffling,and discuss those possibilities with theCaterpillar Application engineer involved.

Record environmental conditions at the timeof the test. If outdoors, note wind directionand velocity relative to the test unit, and itsprobable effect on test results. If indoors, noteair movement, any uneven temperaturedistribution, cell recirculation effects, andanything else possibly affecting test results.

Ambient Capability Determination

Fuel RateIncrease the differential (Top tank-Ambient)by the percentage that the measured fuel rateis below the nominal fuel rate, and vice versa.

AmbientIncrease the differential .5°F for each 10°Fthat the test ambient temperature is below90°F (.5°C for each 10°F below 32°C).

Air ConditionerIncrease the differential:

• 3°F (1.7°C) when a radiator mountedcondenser core is installed, but the unit isnot operating during the test.

• 7°F (4°C) when no radiator mountedcondenser core is installed on the test unit,but will be offered on the model beingtested.

Head Wind 15 mph (24 km/hr). Reduce thedifferential 5°F (3°C), per 15 mph (24 km/hr)or 30 mph (48 km/hr) (as appropriate for theapplication. See Cooling Capability), if nohead wind is available during the test.Exceptions are some low-entry, forward cabmodels which have the radiator installed suchthat it does not receive significant air blastfrom a headwind (Engineering judgmentmust be exercised).

If the test is performed above sea level,decrease the differential by 2.5°F (1.4°C) per 1000 ft.

Additional Cores If the installation utilizes other cooler cores inseries with the radiator (either air side orwater side) which are not rejecting normaloperational heat loads during the test, adjustthe differential accordingly. The amount ofjudgment must be based on prior tests orexperience.

Calculate the ambient capability of theinstallation by subtracting the adjusteddifferential from a 210°/220°/230°F(99°/104°/110°C) top tank temperature.

Caterpillar BrakeSaver (Trucks)If the engine is equipped with a BrakeSaver,or if the truck model will be sold withBrakeSaver equipped engines, the coolingsystem must also be capable of rejectingretarding power. Heat rejection to theradiator based on BrakeSaver rating (includeBrakeSaver, engine friction and fan) isapproximately 36 btu/hp-min (46 kJ/kw-min). The actual value is listed onthe Truck Engine Data Sheet. Field testinghas shown that cooling systems that meet theambient capability cooling recommendations(30 mph ram air) with the 475 hp 3406E Engine will have acceptable coolingcapability for the BrakeSaver.

Review InformationFan information should include supplier partnumber, diameter, number of blades,projected width, fan/shroud relationship andfan/engine speed ratio. Radiator informationshould include supplier and core part number,number of tube rows, and fin description anddensity. Air-to-air chassis mounted coreinformation should include supplier partnumber, internal fin density, and external findensity. Also specify other coolers such as anair conditioner condenser core or oil coolercore which may be mounted in front of theradiator. Include a photograph of installationif possible.

Determine the engine outlet temperature atwhich:

• Water temperature warning devices operate(not required if controlled by electronicengine).

• Shutters start to open and are fully open.• Shutters close.• Fan clutch is engaged (not required if

controlled by electronic engine).

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52

THE COOLING SYSTEM

PlumbingRadiator inlet and outlet diameter coolantconnections should be no smaller than theengine inlet and outlet diameter. Roundcorners on passages are recommended. Giveparticular attention to the coolant pump inletto avoid imposing high pump restrictions withunnecessary bends or small piping. Do not useninety degree mitered joints. Piping betweenthe engine and radiator must be flexibleenough to provide for relative motion betweenthe two. Hoses less than 6 in. (152 mm) inlength provide little flexibility and aredifficult to install. If the hose is more than 18 in. (457 mm) in length, it is susceptible tofailure from vibration or coming loose at theconnections. Support the piping withbrackets, when necessary, to take weight off avertical joint. High quality hose, clamps, andfittings are a prerequisite for long life and toavoid premature failure. It is also necessaryto bead pipe ends to reduce the possibility of ahose blowing off. Double clamps are desirablefor all hose connections under pressure. Ventlines and shunt lines must slope downwardwithout high or low areas that may trap airand cause an airlock. In order to maintain thecorrect flow relationship in the radiator toptank, it is recommended that no lines tee intothe shunt or vent lines and that no lines,other than the shunt line, radiator return,and vent be plumbed into the top tank.

Radiator Vertical FlowTop TankA principal function of the top tank is toprovide coolant deaeration. Air in the coolantis one of the principal causes of water passagecorrosion. In extreme cases, it can cause lossof water pump prime or performance withserious engine damage resulting. It alsoadversely affects heat transfer to the coolant.Some radiators utilize an auxiliary expansionor surge tank where height or volumerestrictions do not permit large top tanks.Additional functions of the top tank areindicated in the design areas as follows:

Radiator InletInlet diameter should be at least equal toengine coolant outlet diameter.

Baffle DesignThe main feature of the shunt system toptank design is a baffle which divides the tankinto an upper and lower section. The maincoolant flow from the engine returns belowthe baffle. The coolant is not in contact withthe top tank air space so it is not possible forthe water to entrain air at this point. Theupper tank section receives water from astandpipe or vent tube through the baffle. Thebaffle must be sealed all around. The top tankbaffle should be positioned so that it creates avolume above the core large enough so thatthe coolant change rate at rated pump flow isno more than 150 changes per minute.

Example:

138 gpm (rated pump capacity) = 145 (acceptable)

.95 gal (below baffle volume)

Shunt Line ConnectionThe shunt line connection is into the upperchamber of the top tank, centered, and as lowas possible. In order to better supplynonturbulent coolant free of air bubbles, thisconnection should be into a well in the baffle.Provide a means to break up a vortex at theshunt line inlet. Slope the shunt lineconnection downward from the top tankconnection. Since the shunt line configurationalso affects fill rate, better coolant fillperformance can be achieved on designswhich extend the top tank rearward from thecore. The shunt line connection can then bemade to drop vertically from the top tank.Unless otherwise specified, the shunt lineshould have a minimum internal diameter of 1.0 in. (25.4 mm).

Baffle Vent TubeThe baffle vent tube (between top and bottomportion of top tank) should be approximately0.3 in. internal diameter but not too large sothat pump cavitation temperature suffers.(0.19 to 0.25 in. {4.8 to 6.4 mm} I.D. has beenfound to be satisfactory for the 3208, 3116,3126, and 3126B Engines.) The vent tube

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must not project below the dividing baffleplate; direct it away from the shunt line wellarea to avoid causing turbulence. Experienceindicates that increasing baffle vent tubediameter provides more air venting ability.However, this side benefit is offset by atendency to produce lower pump cavitationtemperatures as the vent diameter isincreased. Final determination of size andconfiguration is best determined by test.

Engine Vent ConnectionThe engine vent connection should be locatedabove the water level and some distance toone side of the shunt line well.

Low LevelLocate the top tank such that the water levelis always above all extremities of the enginewater jacket. At the minimum level, theshunt line connection must be covered withcoolant at maximum expected tilt angle. AnAdd Coolant level indicator mark isrecommended for each top tank design. Theminimum coolant level is established by arecommended percentage of total coolantsystem volume between full and low marks.The low point is verified by a coolant levelsensitivity or drawdown test. For specificallowable reduction of pump pressure rise andlow level percentage of total system coolantvolume, see the Truck Engine Data Sheet.

For heavy-duty Caterpillar Engines, thisvolume is generally 12% of the total coolantvolume minimum for systems with a 7 psi(48 kPa) pressure cap minimum; 16% of thetotal coolant volume minimum for systemswith less than 7 psi pressure cap. Use 9% ofthe total system as the low level for 3208,3116, 3126, and 3126B Engines. Consider thisvolume as the working range of the coolantlevel. The bottom end is the minimum coolantlevel and the top end can be brimful. Thevolume is established by experience and iscomprised of expansion volume, after boilvolume and makeup volume.

Low Level IndicatorsTypes of low level indicators that have beenfound to be satisfactory are:

Metal PlateA metal plate uncovered by low coolant. Thedevice is commonly used on the top tanks ofCaterpillar products. It could be an additionalplate or even an upward protrusion of thebaffle plate. The low level plate shouldcontain a hole to drain any coolant pockets toavoid a false level indication.

Sight WindowThis device has had some success. Two sightscan easily be used to show high and lowmarks to give a go or no-go decision.

Downward Extension of the Filler Pipe This design should be treated carefully. Anatural tendency is for the fill to stop at thefill pipe bottom (not run the level high enoughin the fill pipe). The filler pipe can be cutaway up to the high level mark with ahorizontal plate attached which would beuncovered to show the low level. If adownward extension is used, a vent cross holemust be made at a level as high as possible.This permits use of the air space above thehigh level indicator as expansion volume. Anyair trapped in the top tank above the crosshole (while not harmful) is not included in thecoolant system expansion volume calculation.

Low Level AlarmIn addition to low level indication, a lowcoolant alarm can be used. It should bepositioned to be activated at or below the lowlevel. The C-10, C-12, and 3406E Engineshave low level alarm features.

Bottom TankThe bottom tank, because of its simplicity, iseasily overlooked as important to coolingability. Good bottom tank design includesthese considerations:

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Outlet PipeCoolant outlet pipe should be locateddiagonally opposite or as far from the coolantinlet as possible. This will provide moreuniform coolant flow across the core andprevent direct flow between the coolant inletand outlet.

Restrictions to coolant flow may be reduced byrounding the cooling outlet joint connectioninstead of leaving a sharp edge at the jointbetween the outlet tube and bottom tank. Sizethe outlet tube the same as the engine inletpipe or opening.

DrainsDrains should always be threaded plugs. Gateor globe drains are vulnerable to vibration.They are not recommended because of theease by which they can be accidentally openedor broken off.

HeightBottom tank height should be no less than thediameter of the outlet pipe.

Radiator Horizontal (Cross) Flow While some of the rules for vertical flowradiators also apply to the cross flow radiator,there are enough differences so that the crossflow design subject should be treatedseparately.

Caterpillar policy is to refer questionsregarding cross flow radiator design(especially in respect to water flow and airventing) to a radiator manufacturer of thetruck builder’s choice. However, coolingsystem performance criteria is the same as forvertical flow radiator designs.

Radiator CoreSize the core frontal area as large as possibleto minimize restriction to airflow. Lowradiator core restriction usually results in theability to provide a larger diameter, quieter,slower turning fan, which demands less drivehorsepower (vehicle restriction should not beignored). Radiators which are nearly squarecan provide the most effective fan

performance. They can be installed with aminimum of unswept core area. As a generalrule, keep core thicknesses to a minimumwith a minimum of 11 fins per inch.Increasing the number of fins per inch doesincrease the radiator heat rejection for a givenair velocity through the core, but at a cost ofincreasing the resistance to air flow. Whilethe most economical initial cost will bemaximum core thickness and fins per inch,this involves higher fan horsepower withconsequent operating penalties throughoutthe life of the installation. In addition, aradiator with more fins per inch is moresusceptible to plugging from insects anddebris.

Heat transfer capacity must be sufficient tomeet the minimum ambient temperaturerecommendation shown in the Truck EngineData Sheet. This is the ambient air whichraises the temperature of the coolant leavingthe engine to the radiator to 210°F/220°/230°F(98°C/104°/110°C) under these conditions:water as coolant, 15 mph (24 km/h) ram airand operating air conditioner. Installing an oilcooler or air conditioner condenser in thefront of the radiator is the same as increasingradiator core thickness. Consideration mustbe given to the reduction in airflow andhigher ambient temperatures to the radiatorwhen cooling air flows first through the heatexchanger. Experience indicates that the lossin cooling capability due to an air conditioningcondenser is the equivalent of 3 to 7°F (1.66 to3.88°C) rise in ambient temperature. Makeprovision for easy inspection and cleaning ofthe area between cores, since debris is easilytrapped between the two cores.

Radiator Filler CapA filler cap with 7 psi (48 kPa) minimumpressure relief is recommended with engineshaving a maximum top tank temperature of210°F (99°C). For engines with a maximumtop tank temperature of 220°F (104°C), aminimum pressure relief of 9 psi isrecommended. A 14 psi (97 kPa) minimumpressure relief cap is recommended forengines having a maximum top tanktemperature of 230°F (110°C).

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Radiator MountingMany types and styles of radiator mountingsare in use. These depend at least in part onthe radiator design. The important point isthat some deflection of the vehicle structure isinevitable. Preventing these deflections frombeing transmitted into the radiator core isimportant.

Transmission and Retarder Oil CoolersWhen a torque converter oil cooler is added tothe engine cooling system, the total heat loadis the sum of the heat rejection by the engineand the torque converter. To size a radiatorfor a torque converter, the additional heatload can readily be calculated as heat rejectedin Btu/minute = 42.4 x bhp x(100 - Converter Efficiency)/100. For an off-highway application, 70% efficiency point isnormally used. An efficiency of 80% is usedfor an on-off highway application. Heatrejection values at various converter efficiencypoints can also be obtained from mosttransmission suppliers.

Ambient capability at rated and peak torque+100 conditions must be met as listed formanual transmissions. An automatictransmission may not allow operating at thepeak torque +100 point, in which case theengine should be lugged to 100 rpm above thelowest speed before downshifting.

The 80% converter efficiency point ambientcapability for on-off highway applicationsshould be the same as listed for peak torque+100 rpm. The only exception is for line haulapplications with transmissions that haveconverter lockup in the top gears. These linehaul applications can be treated as manualtransmission applications. Cement mixers,pickup and delivery, RV’s, buses and garbagepackers do not qualify as line haulapplications. Because of the variety ofautomatic transmissions with torqueconverters available and the difference intheir operation, consult the transmissionsupplier for cooling system design criteria.

Use an automatic high water temperaturealarm whenever a transmission cooler is partof the engine cooling system. Set it for

5°F±2°F above the maximum recommendedtop tank temperature. This alarm is notintended to be used in lieu of meeting theambient capability goals.

Hydraulic retarder coolers, which have higherheat loads, have the same requirements astorque converter coolers. Heat load, however,is calculated at 100% efficiency. The bestlocation for the retarder or torque convertercooler is on the coolant pump discharge beforethe coolant enters the engine. Caterpillaroffers mounted auxiliary coolers in thislocation for some engines. An alternate coolerlocation is in the radiator bottom tank orbetween the bottom tank and the coolantpump inlet. This is the preferred locationwhen a Caterpillar Engine mounted coolercannot be used. Set an automatic high watertemperature alarm for 5°F±2°F above themaximum recommended top tanktemperature. Equip the CaterpillarBrakeSaver with a high oil temperaturewarning light.

Fan RecommendationsDiameter and SpeedAs a general rule, the most desirable fan isone having the largest diameter and turningat the lowest speed to deliver the requiredairflow. This also results in lower fan noise.Blade tip speed, while one of the elements ofcooling fan design, is easily changed withchoice of fan drive pulley diameter. Anoptimum fan tip velocity of 14,000 ft/min(7112 cm/s) is a good compromise for meetingnoise requirements and cooling systemperformance requirements.

Fan PerformanceProper selection and placement is critical tothe efficiency of the cooling system. Itrequires careful matching of the fan andradiator by determining airflow needed andstatic air pressure which the fan mustovercome. This must be done since mostdiscrepancies between cooling systemcalculated performance and test results aretraceable to the "air side" and directly relatedto items affecting fan airflow.

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SelectionThere are two major considerations for properfan selection:

AirflowAirflow needed to provide the requiredcooling.

SensitivitySelect a fan that provides the requiredairflow, and is relatively insensitive to smallchanges in static pressure, such that a smallchange in static pressure does not cause alarge change in airflow. Selecting a lowerpressure point is not recommended as it couldbe in the unstable stall area where a smallchange in static pressure causes a largechange in air flow. Performance curves foravailable Caterpillar fans are shown asAirflow (CFM), Static Pressure Head (inches of water, gauge), and Horsepower. TheCaterpillar curves are based on standard airdensity, an efficient fan shroud, .38 inch (9.7 mm) tip clearance, and no obstructions.This is a theoretical air flow which is seldompossible because of vehicle obstruction.Theoretical airflow sometimes can beapproached with the fan in a properlydesigned engine mounted shroud. Such aclose fitting shroud seldom is practical and tipclearance must be increased. A minimum of0.5 in. (12.7 mm) clearance is generallyrequired. When a fan speed different fromthose shown in the curves is needed, theadditional performance data can be calculatedusing these fan rules:

Fan Laws• Airflow varies directly with rpm.• Static pressure head varies with rpm.• Horsepower varies with rpm3.

Fan Shrouds and Fan LocationTwo desirable types of shrouds are Venturiand Box.

Maximum airflow and efficiency is providedby a tightfitting Venturi shroud. Small fanclearances require a fixed fan or an adjustableshroud. Although they are somewhat lessefficient than the Venturi shroud, box-typeshrouds are most commonly used. Properly

positioned, a simple orifice opening in the boxshroud is practical. The fan tip clearancemust be 0.5 in. (12.7 mm) or less. Fanengagement into the shroud should generallyequal 2/3 of the projected blade width (checkwith fan manufacturer for proper fan toshroud engagement). A properly designedshroud will:

• Increase airflow.• Distribute airflow across the core for more

efficient use of available area.• Prevent recirculation of air.As a general rule, position suction fans shouldbe no closer to the core than the projectedblade width of the fan. Greater distance givesbetter performance. Consider also thatengine-mounted items mounted close to theback side of the fan can introduce vibrationsinto the fan to cause fan failure and/orincrease fan noise.

Air Flow Losses and EfficiencyObstructionsGive particular attention to items restrictingairflow, both in front of the radiator and to therear of the fan. The additive effects of guards,bumpers, grills and shutters in front of theradiator, pulleys idlers, engine-mountedaccessories and the engine itself behind thefan, can drastically reduce airflow.

Air Recirculation BafflesExperience indicates that cooling during lowvehicle speed operation can be appreciablyimproved by sealing around the radiator toprevent air from inside the enginecompartment being recirculated back into thefront of the radiator core. The usual method isto bolt or rivet strips of sheet gasket materialto the truck sheet metal or the radiatormounting bracket to close the area around theradiator. The baffles are customarily fastenedon only one edge so as to provide maximumflexibility. The material used should be oilresistant and suitable for the temperaturesinvolved. The baffle material must be rigidenough and must be located in such a mannerthat it is not displaced by ram air at highervehicle speeds.

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Installation experience has shown totalsystem efficiency in the range of 45% to 70%.Loss factors, in addition to air restriction,include: Air density (temperature andaltitude) that affects both fan flow andradiator heat rejection, fan tip clearance,shroud efficiency, and recirculation losses.While the value for each of these items maybe estimated, test the pilot model todetermine if airflow problems exist.

Blower FansSuction fans are generally used on all trucksto compliment ram air. Blower fans are usefulonly when engines are located in the rear of avehicle.

Fan Drive Overhanging MomentThe fan and temperature controlled fan drivemust not exceed the design parameters forbearings, brackets, and other installationhardware. For Caterpillar Truck Engine fandrives, the maximum additional momentabout the fan bracket to engine mountingface (for fan, thermatic drive, or spacer) isas follows:

• 3116, 3126, and 3126B fan drive - consultfactory.

• 3208 fan drive with taper roller bearing (Ref. 9N1387) 135 in-lb (15.2 N•m).

• 3208 fan drive with cartridge ball bearing (Ref. 9N0793).

• 95 in. lb. (10.7 N•m).• C-10, C-12 fan drive - N/A.• 3306 fan drives 136 in-lb (15.3 N•m).• 3406 fan drives 356 in-lb (40.2 N•m).

F = weight of fan + thermatic drive or spacer

L = distance from fan bracket mounting faceto the center of gravity of the addedweight (fan, thermatic drive, spacer)

Maximum additional moment = F x L

Typical Fan Drive

Figure 6

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Temperature ControlMinimum TemperatureWhen the coolant operating temperature isbelow 160°F (70.4°C), the engine is consideredovercooled. Low engine operatingtemperatures accelerate the deterioration ofthe lube oil additives which are formulated tominimize the corrosive effect of the sulfuricacid formed from combustion by-products andthe corresponding increase in engine wear.

ShuttersRadiator shutters are used to help controlcoolant minimum temperatures. Also seeparagraph Radiator Shutters/Winter Frontsunder Air-to-Air AfterCooling Systems. Whenusing shutters, consider these items:

• Air restriction: some designs can reduceairflow as much as 20%.

• Extra space is required for the louver frame.Shutter opening is controlled automaticallyby shutterstats. Currently, shutter systemsfall into two classes - snap type (air operated), which are fully open or fullyclosed, and modulating type, which open andclose gradually.

Shutterstat SettingsCaterpillar Engines are equipped with eithera 180°F (82.2°C) or 190°F (87.8°C) start-to-open temperature regulator (thermostat).With the 180°F (82.2°C) regulator and otherthan a viscous fan drive, the recommendedmaximum shutterstat setting for opening thesnap type shutters is 195°F (90.6°C); and withthe 190°F (87.8°C) regulator, therecommended maximum shutterstat openingsetting is 200°F (93.3°C). When a viscous fandrive is used, the maximum shutterstatopening setting should be 170°F (76.7°C) toallow the shutters to open before the fan isfully engaged. With the modulating typeshutters, the shutter control is normallylocated in the radiator bottom tank; thus, therecommended shutter opening temperature isthe same as the engine coolant regulator startto open temperature.

Thermatic Fan DrivesA thermatic or thermostatically controlled fandrive may also be used (with or withoutshutters) to improve temperature control, fueleconomy and noise. Thermatic fan drives aresupplied in three types: on-off, modulating,and viscous. The recommended fan controlcoolant temperature setting for the on-off fanclutches is to have the fan turn on 5°F (2.7°C)below the maximum allowable top tanktemperature shown in the Truck Engine DataSheet. One exception is the 3126 and 3126Bengines where the fan clutch turn ontemperature should be 205°F (96.1°C). For aviscous fan drive, refer to manufacturer forthe engagement temperature range.

For vehicles that do not have ram air to theAir-to-Air AfterCooler system, an additionalcontrol is required to turn the fan on whenthe air to the engine (from the aftercoolercore) is above 150°F.

Shutterless OperationShutters are not a requirement on Caterpillarengines; however, they will help to maintainthe minimum coolant operating temperaturein cold climates.

Certain combinations of extremely lowambient temperatures and heat loss fromengine convection can result in overcoolingand insufficient cab heater output. Theaddition of radiator shutters or a cover winterfront are solutions to this problem.

Gauges and DevicesWater Temperature GaugesThe size and location of the watertemperature gauge connection is shown onthe Engine General Dimension Drawing. Becertain the temperature bulb is located in thewater flow. Use of a pipe fitting reducer mayremove the bulb from the coolant stream andcause an erroneous reading. The gaugeshould be marked with a red band or warningat the maximum top tank temperature210°F/220°/230°F and above.

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Warning and Shutdown DevicesA large number of warning devices areavailable to indicate high coolanttemperature, low radiator tank level, loss ofcoolant flow and air in the water. Install themin accordance with the manufacturer’srecommendations. Set a cylinder headmounted sensing unit so that a warning isgiven at a top tank temperature of 5°F abovethe maximum allowed top tank temperature(210/220°/230°F [99°/104°/110°C]). Caterpillarrecommends this device be part of everyinstallation and should be of high quality withaccuracy of ±2°F. Depending on engine model,mount this unit in the cylinder head orcoolant regulator housing to monitor thecoolant temperature before it leaves theengine to the radiator top tank.

When a shutdown device is used, set itto shutdown the engine at a top tanktemperature of 10°F (5.6°C) above themaximum allowed top tank temperature(210/220°/230°F [99°/104°/110°C]).

Coolant HeatersDevices which heat engine coolant to providefaster engine warmup are commonly calledengine block heaters. They fall into twocategories:

• Internal or immersion type• External or tank type.Correct installation of the external typeis very important to ensure adequatecoolant circulation through the cylinderblock and heads when the heater isoperating, and to avoid overheating causedwhen coolant recirculates through the heaterduring normal engine operation. Theprinciple involved in operation is calledthermosyphoning. The heated coolant risesin the tank or block. Since the coolant systemis a closed loop, the rising hot coolant will bereplaced by cold coolant and circulationresults. To prevent coolant bypassing thecylinder heads during engine operation, a

check valve must be included in the blockheater circuit. Many external heaters havebuilt-in check valves, but test the heater firstbefore installing it to be sure. Pour water inthe outlet of the heater the check valve. Itshould prevent the water from flowingthrough the heater. If the block heater chosendoes not contain an integral check valve, onemust be installed. Install the check valve onthe inlet side of the tank.

The inlet to the heater can be taken fromeither the top of the engine or the pump inlet.

With a cold engine condition, the radiatorbypass line becomes the conduit from thecylinder head to the pump inlet.

Direct the outlet from the heater tank upwardto the engine connection with no loops ordownward turns. If the engine connection ismade at the normal block drain, a tee fittingand drain plug in this line is recommended.

Coolant ConnectionsCoolant connections on Caterpillar Engines,for coolant using devices, fall into one of fourclassifications as follows:

Pump DischargeThis is a maximum pressure coolant; apressure tap is always available for testhookups. When devices require maximumpressure drop across them to get maximumcoolant flow, this location is used for supply.The engine return connection is at the waterpump inlet. Some engines do not provideaccess to the pump discharge for coolantusing devices.

After Engine Oil CoolerThis is high coolant pressure. The pressurewill be pump discharge pressure minusengine oil cooler pressure drop. Temperaturewill have been raised slightly from pumpdischarge temperature. This location is notprovided on all engines.

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Top of EngineThis is maximum temperature coolant. Toplocations can be on the cylinder head or thefront cover, but conventionally they arelocated on the regulator housing. Coolant atthis location will be approximately 8 to 15°F(4.44 to 8.33°C) higher in temperature than atthe pump outlet. Pressure will be lower thanat the pump discharge or after the engine oilcooler. Some devices can use this location forreturn coolant if supply has been taken at thepump discharge. Engine temperature willalways be taken at the top of the engine.

Pump Inlet This is minimum pressure coolant. Mostcoolant using devices will return coolant tothis location. The radiator shunt line isconnected here. A test tap is always locatedhere.

Additional Cooling System Connections

Engine VentGenerally, this is located on the highest accessto the engine in order to most efficiently bleedair from the engine to the radiator top tank.

Location of Coolant ConnectionsThe Truck Engine Installation Drawings bookidentifies all of the coolant connections foreach engine. The size and exact location isalso provided.

COOLANT INFORMATION

NOTICE

Adding coolant to an overheated enginecould result in damage to the engine.Allow the engine to cool before addingcoolant.

If the vehicle is to be stored in, orshipped to, an area with freezingtemperatures, the cooling system mustbe protected to the lowest outside(ambient) temperature.

Air pockets can form in the cooling system, ifthe cooling system is filled at a rate that isgreater than 20 L (5 US gal ) per minute.

Never operate without a thermostat in thecooling system. Cooling system problems canarise without a thermostat.

Many engine failures are related to thecooling system. Cooling system failuresinclude the following problems: overheating,leakage of the water pump, plugged radiators,and cylinder liner pitting. These failurescould be avoided with proper cooling systemmaintenance. Maintenance of the enginecoolant is important to the engine life and tothe performance. This maintenance is asimportant as fuel quality. This maintenance isas important as the maintenance of thesystem for lubricating oil.

Coolant provides three main functions:• Cooling - to provide adequate heat transfer• Corrosion protection - for cavitation erosion/

corrosion protection• Anti-boil/freeze protection

Coolant is normally composed of threeelements:

• Water• Additives• Glycol

Water

NOTICE

Never use water alone without Supple-mental Coolant Additive (SCA’s) orinhibited coolant. Water alone is corro-sive at engine operating temperaturesand does not provide adequate boilprotection.

Water functions as the heat transfer portionof a coolant. For this reason, it is important touse water that meets the followingrecommendations. Water that does not meetthe recommendations can interfere with heattransfer and can be corrosive.

Distilled water or deionized water isrecommended for use in cooling systems. Donot use hard tap water or salt softened tapwater in engine cooling systems. If distilledwater or deionized water is not available, usewater that meets the minimum requirementsthat are listed in the following table.

1 See “ASTM D512b”, “ASTM D512d”, or “ASTM D4327”.2 See “ASTM D516b”, “ASTM D516d”.3 See “ASTM D1126”.4 See “ASTM D1888a”.5 See “ASTM D1293”.

For a water analysis, consult one of thefollowing organizations:• The Caterpillar Laboratory for an S•O•S

Analysis• The LOCC Corporation• Local water department• Agricultural agent• Independent laboratory

AdditivesCoolant additives help in the following ways:• Preventing rust from forming• Preventing scale and mineral deposits from

forming• Protecting metals from corroding• Preventing cavitation of the liner• Preventing coolant from foaming

Many additives are depleted during engineoperation and these additives need to bereplaced. This can be done through the

addition of Supplemental Coolant Additives(SCA) to Diesel Engine Antifreeze/Coolant(DEAC) or by adding Extender to ExtendedLife Coolant (ELC).

Additives must be added at the properconcentration. Overconcentration of additivescan cause the inhibitors to drop out-of-solution. This can cause a gel compound toform in the radiator. An overconcentration ofadditives can produce deposits on water pumpseals that can cause water pump seal leakage.A low concentration of additives can producethe following problems:• Pitting• Cavitation erosion• Rust• Scale• Foaming

GlycolGlycol in the coolant provides anti-boilprotection and freeze protection. Glycol in thecoolant prevents water pump cavitation.Glycol in the coolant also reduces cylinderliner pitting. For optimum performance,Caterpillar recommends a solution thatcontains a 1:1 mixture of water and of glycol.

Note: Caterpillar engines with air-to-airaftercooling require a minimum of 30 percentglycol in order to prevent water pumpcavitation.

Most conventional heavy-dutycoolant/antifreezes use ethylene glycol.Propylene glycol may also be used. In amixture that is 50 percent water, ethyleneglycol and propylene glycol have similarproperties that are relative to the followingelements: heat transfer, freeze protection,control of corrosion, and compatibility of theseal. Check the glycol level of the coolantsystem with the lU-7298 Coolant TesterGroup (°C) or with the 1U-7297 CoolantTester Group (°F). Tables 2 and 3 define thefreeze protection for ethylene glycol and forpropylene glycol.

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Caterpillar Recommended Water Quality Limits

Table 1

PPMWater Property mg per liter

grains/US gal

MaxMax

Chloride1 (CI) 40 2.4

Sulfate2 (SO4) 100 5.9

Total WaterHardness3 170 10

Total Solids4 340 20

Acidity5 5.5 pH to 9.0 pH

NOTICE

Do not use propylene glycol in concen-trations that exceed 50 percent glycolbecause of propylene glycol’s reducedheat transfer capability. Use ethyleneglycol in conditions that require addi-tional freeze or anti-boil protection.

COOLANT RECOMMENDATIONSThe following two coolants are used inCaterpillar machine engines:

Preferred – Caterpillar Extended LifeCoolant (ELC) or a commercial ELC thatmeets the Caterpillar specification (EC-1)

Acceptable – A Caterpillar Diesel EngineAntifreeze/ Coolant (DEAC) or a commercialheavy-duty coolant/antifreeze that meets“ASTM D4985” or “ASTM D5345”specifications

NOTICE

Do not use a commercial coolant/anti-freeze that only meets the “ASTM D3306”specification. This type of coolant/anti-freeze is made for light duty automotiveapplications.

Caterpillar recommends a 1:1 mixture ofwater and glycol. This mixture of water andglycol will provide optimum heavy-dutycoolant/antifreeze performance.

Note: Caterpillar DEAC does not requirea treatment with an SCA at the initial fill.A commercial heavy- duty coolant/antifreezethat meets “ASTM D4985” or “ASTM D5345”specifications requires a treatment with anSCA at the initial fill.

Extended Life Coolant (ELC)Caterpillar provides Extended Life Coolant(ELC) for use in the following applications:• Heavy-duty diesel engines• Natural gas engines• Automotive applications

The Caterpillar ELC anti-corrosion package isdifferent than other coolants. Caterpillar ELCis an ethylene glycol base coolant. However,Caterpillar ELC contains organic corrosioninhibitors and antifoam agents with fewernitrites than other coolants. Caterpillar ELChas been formulated with the correct amountsof these additives in order to provide superiorcorrosion protection for all metals in thecooling system of diesel engines.

Caterpillar ELC extends the service life of thecoolant to 600,000 miles or six years. ELCdoes not require the frequent additions of aSupplemental Coolant Additive (SCA). AnExtender is the only additional maintenancethat is needed at 300,000 miles or one-half ofthe service life.

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Ethylene Glycol

Freeze Anti-Boil Concentration

Protection Protection

50 Percent –36°C (–33°F) 106°C (223°F)

60 Percent –51°C (–60°F) 111°C (232°F)

Table 2

Coolant Service Life

Coolant Type Service Life

Caterpillar ELC966,000 km (600,000 mi)

or Six Years

Caterpillar DEAC322,000 km (200,000 mi)

or Two Years

Commercial heavy duty322,000 km (200,000 mi)

coolant/antifreeze meetingor Two Years

ASTM D5345 or TMC RP329

Commercial heavy duty241,500 km (150,000 mi)

coolant/antifreeze meetingor One Year

ASTM D4985

Table 4Propylene Glycol

Freeze Anti-Boil Concentration

Protection Protection

50 Percent –29°C (–20°F) 106°C (223°F)

Table 3

ELC is available in a 1:1 premixed coolingsolution with distilled water. A 1:1 premixedsolution of ELC will lower the freezing pointto –36°C (–33°F). ELC Concentrate can beused to lower the freezing point to –51°C(–60°F) for arctic conditions.

Containers of several sizes are available.Consult your Caterpillar dealer for the partnumbers.

ELC can be recycled. The drained coolantmixture can be distilled in order to removethe ethylene glycol and the water. Theethylene glycol and the water can be reused.Consult your Caterpillar dealer for moreinformation.

Commercial ELCIf Caterpillar ELC is not used, then select acommercial ELC that meets the Caterpillarspecification of EC-1 and either the “ASTMD5345” specification or the “ASTM D4985”specification. Do not use a long life coolantthat does not meet the EC-1 specification.Follow the maintenance guide for the coolantfrom the supplier of the commercial ELC.Follow the Caterpillar guidelines for thequality of water and the specified coolantchange interval.

ELC Cooling System MaintenanceCaterpillar ELC ExtenderCaterpillar ELC Extender is a liquid that isadded to the cooling system halfway throughthe ELC service life.

NOTICE

When using Caterpillar ELC, do not usestandard SCA’s or SCA filters. To avoidSCA contamination of an ELC system,remove the SCA filter base and plug offor by-pass the coolant lines.

The cooling system should be treated withExtender at 483,000 km (300,000 miles) (one-half of the service life). Use Table 5to determine the required amount of theCaterpillar Extender.

Changing to Caterpillar ELCTo change from heavy-duty coolant/antitreezeto the Caterpillar ELC, perform the followingsteps:

1. Drain the coolant into a suitablecontainer.

2. Dispose of the coolant according to localregulations.

NOTICE

Do not leave an empty SCA filter on anELC system.The filter housing may corrode and leakcausing an engine failure.Remove the SCA filter base and plug offor by-pass the coolant lines.

3. Flush the system with clean water inorder to remove any debris.

4. Use Caterpillar cleaner to clean thesystem. Follow the instructions onthe label.

5. Drain the cleaner into a suitablecontainer. Flush the cooling system withclean water.

6. Fill the cooling system with clean waterand operate the engine until the engine iswarmed to 49 to 66°C (120 to 150°F).

7. Drain the cooling system into a suitablecontainer and flush the cooling systemwith clean water.

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Amounts of the Caterpillar ELCExtender by Cooling System Capacity

Table 5

RecommendedCooling System Capacity Amount of

Caterpillar Extender

22 to 30 L (6 to 8 US gal.) 0.57 L (20 fl. oz.)








8. Repeat Steps 7 and 8 until the system iscompletely clean.

9. Fill the cooling system with theCaterpillar ELC.

10. Attach the Special Publication PEEP5027,“Label” to the radiator on the vehicle inorder to indicate the use of CaterpillarELC.

Note: Clean water is the only flushing agentthat is required when the ELC is drainedfrom the cooling system.

Contamination of the ELC Cooling System

NOTICE

Mixing ELC with other products re-duces the effectiveness of the coolantand shortens coolant life. Use onlyCaterpillar products or commercialproducts that have passed theCaterpillar EC-1 specification for pre-mixed or concentrate coolants. Use onlyCaterpillar Extender with CaterpillarELC. Failure to follow these recommen-dations can result in shortened coolingsystem component life.

In cooling systems that use Caterpillar ELC,do not add Diesel Engine Antifreeze/Coolant(DEAC) as a makeup coolant. Contaminationof ELC by DEAC will defeat the advantagesof ELC. If the ELC in the cooling systembecomes contaminated by more than 10percent of the total system capacity of DEACor SCA, perform one of the followingoperations:

• Drain the cooling system into a suitablecontainer. Dispose of the coolant accordingto local regulations. Flush the system withclean water. Fill the system with theCaterpillar ELC.

• Maintain the system as a conventionalDiesel Engine Antifreeze/Coolant (DEAC).Treat the system with an SCA. Change thecoolant at the interval that is recommendedfor the conventional Diesel EngineAntifreeze/Coolant (DEAC).

Extended Life Coolant (ELC)Cooling System Maintenance

NOTICE

Use only Caterpillar products or com-mercial products that have passedCaterpillar EC-1 specification for pre-mixed or concentrated coolants.Use only Caterpillar Extender withExtended Life Coolant.Mixing Extended Life Coolant withother products reduces the ExtendedLife Coolant service life. Failure tofollow the recommendations can re-duce cooling system components lifeunless appropriate corrective action isperformed.

For the correct balance of antifreeze and ofadditives, proper care should be taken inorder to maintain the concentration ofExtended Life Coolant (ELC). Lowering theproportion of antifreeze lowers the proportionof additive. This will lower the ability of thecoolant to protect the system from pitting,from cavitation, from erosion, and fromdeposits.

Proper additions to the Extended Life CoolantNote: Do not add ELC Concentrate as amakeup solution for a routine cooling systemtop-off. The addition of the concentratedExtended Life Coolant will increase theconcentration of glycol in the cooling system.

During the normal maintenance, use thepremixed ELC as a cooling system top-off.This will bring the coolant up to the properlevel. Use ELC or use a coolant that meetsCaterpillar specifications (EC-1). If the propercoolant is not available, use distilled water oruse deionized water. Check the glycol level ofthe coolant system with the 1U-7298 CoolantTester Group (°C) or with the 1U-7297Coolant Tester Group (°F). Use ELCConcentrate to restore the proper glycolconcentration in the coolant system. Thisshould be done before the engine is exposedto freezing temperatures.

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65

NOTICE

Do not use a conventional coolant to top-off a cooling system using Extended LifeCoolant.Do not use supplemental coolant addi-tives (SCA) other than Extender incooling systems filled with ExtendedLife Coolant.

Extended Life Coolant CoolingSystem CleaningNote: Cleaning agents are not required tobe used at the coolant change interval if thecooling system is already using ELC.Cleaning agents are only required if thesystem has been contaminated by theaddition of some other type of coolant or bycooling system damage.

Clean water is the only cleaning agent thatis required when ELC is drained from thecooling system.

ELC can be recycled. The drained coolantmixture can be distilled. The distillationprocess can remove the ethylene glycol andthe water. Consult your Caterpillar dealerfor more information.

After you drain the cooling system and afteryou refill the cooling system, operate theengine while the radiator filler cap isremoved. Operate the engine until the coolantreaches the normal operating temperatureand until the coolant level stabilizes. Asneeded, add the coolant mixture in order tofill the system to the proper level.

Diesel Engine Antifreeze/Coolant (DEAC)In cooling systems that use a heavy-dutycoolant/antifreeze, Caterpillar recommendsthe use of a Caterpillar Diesel EngineAntifreeze/Coolant (DEAC). CaterpillarDEAC is an alkaline single-phase ethyleneglycol type antifreeze that contains corrosioninhibitors and antifoam agents.

Caterpillar DEAC is formulated with thecorrect amount of Caterpillar SupplementalCoolant Additive (SCA). Do not use SCA at

the initial fill when DEAC is used. The coolantshould be sampled after every 24,150 km(15,000 miles) of operation. The results ofthe coolant sample will regulate theadditions of the SCA. The life of the coolantfor the Caterpillar DEAC is 322,000 km(200,000 miles) or every two years.

Caterpillar DEAC is available as eithera concentrate or a 1:1 premixed coolingsolution. If concentrated Caterpillar DEACis used, Caterpillar recommends dilution withdistilled water or with deionized water. Ifdistilled water is not available or deionizedwater is not available, refer to CoolantInformation in order to determine therequirements for acceptable water.

Commercial Heavy-Duty Coolant/Antifreeze and SCAIf Caterpillar DEAC is not used, select aheavy-duty coolant/antifreeze with a lowsilicate content that meets “ASTM D4985”or “ASTM D5345”. When a commercial heavy-duty coolant/antifreeze is used, thesystem must be treated with Caterpillar SCAto a concentration level that is between3 percent and 6 percent by volume of thesystem. If a Caterpillar SCA is not used,select a commercial SCA with a minimumconcentration of 1200 mg per Liter (70 grainsper gallon) or 1200 parts per million ofnitrites. Follow the SCA recommendedguidelines for the maintenance of the coolant.In all cases, the Caterpillar guidelines foracceptable water must be followed.

Note: When you are not using a CaterpillarDEAC, the cooling system must be drainedonce during every year. The cooling systemmust be flushed at this time as well.

Cooling System Maintenance

NOTICE

Never operate without thermostats inthe cooling system. Thermostats main-tain the engine coolant at the properoperating temperature. Cooling sys-tem problems can develop withoutthermostats.

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Check the solution of coolant/antifreeze(glycol concentration) frequently in orderto ensure adequate freeze protection andprotection from boiling. Check the glycollevel of the coolant system with the 1U- 7298Coolant Tester Group (°C) or with the 1U-7297 Coolant Tester Group (°F). Consultyour Caterpillar dealer for information oncoolant testers.

Supplemental Coolant Additive (SCA)Caterpillar SCA effectively prevents corrosionon all metals and Caterpillar SCA effectivelyprevents the formation of mineral deposits.Caterpillar SCA also prevents cavitation ofthe liner and Caterpillar SCA eliminatesfoaming of the coolant.

Test the SCA concentration or submit acoolant sample to your Caterpillar dealer atevery oil change. After every 24,150 km(15,000 miles), liquid SCA or a SCAmaintenance element may be needed. SCAadditions are based on the results of coolantanalysis. Your Caterpillar dealer has test kitsthat will evaluate the concentration ofadditives in Caterpillar DEAC.

The following table indicates the amount ofCaterpillar SCA that is needed at the initialfill to treat commercial heavy-dutycoolant/antifreezes. The table also shows theaddition of an SCA for either liquid SCA or forthe maintenance elements of a SCA. Theseadditions are for commercial heavy-dutycoolant/antifreezes and for Caterpillar DEAC.

Caterpillar SCA Requirements for Heavy-Duty Coolant/Antifreezes

Caterpillar Liquid SCA Spin-on ElementCooling System 24,150 km (15,000 mi) 24,150 km (15,000 mi)

Capacity in L (US gal) Initial Fill1

Maintenance2 Maintenance

22 to 30 (6 to 8) 0.95 L (32 oz) 0.24 L (8 oz) or one unit 6V-3542 111-23703

one unit 3P-2044

31 to 38 (8 to 10) 1.19 L (40 oz) or one unit 0.36 L (12 oz) or 111-23693

3P-2044 and 6V-3542 one unit 111-2372

39 to 49 (10 to 13) 1.42 L (48 oz) or one unit 0.36 L (12 oz) or 111-23693

3P-2044 and 8T-1589 one unit 111-2372

50 to 64 (13 to 17) 1.90 L (64 oz) or 0.47 L (16 oz) or one unit 8T-1589 9N-33683

two units 3P-2044

65 to 83 (17 to 22) 2.37 L (80 oz) or two units 0.60 L (20 oz) or one unit 111-23713

3P-2044 and one unit 8T-1589 111-2372 and 6V-3542

84 to 114 (22 to 30) 3.32 L (112 oz) or three units 0.95 L (32 oz) or one unit 3P-2044 9N-37183

3P-2044 and one unit 8T-1589

115 to 163 (30 to 43) 4.75 L (160 oz) or 1.18 L (40 oz) or one unit two units 111-23713

five units 3P-2044 3P-2044 and 6V-3542

164 to 242 (43 to 64) 7.60 L (256 oz) or 1.90 L (64 oz) or two units 9N-37183

eight units 3P-2044 two units 3P-2044

Table 6

1 Use a Caterpillar SCA when you do not use a Caterpillar Antifreeze.2 Do not exceed the 6 percent maximum concentration. Check with the supplemental coolant additive test kit.3 Element Assembly.

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Note: Due to the individual engineapplications, the maintenance practices needto be periodically reviewed in order tomaintain the cooling system.

Conventional Coolant/AntifreezeCooling System MaintenanceWhen you initially fill the cooling system withCaterpillar Diesel Engine Antifreeze/Coolant,it is not necessary to add a SupplementalCoolant Additive. Caterpillar Diesel EngineAntifreeze/Coolant already containssupplemental coolant additive. When youinitially fill the cooling system with acommercial coolant that meets therequirements of “ASTM D4985”, add asupplemental coolant additive. Thesupplemental coolant additive in CaterpillarDiesel Engine Antifreeze/Coolant and incommercial coolants must be replenished atregular service intervals. See the table forSupplemental Coolant Additive (SCA) inorder to determine the correct quantity ofliquid supplemental coolant additive to use.

Supplemental Coolant Additive ElementPlumbingThe following plumbing recommendationsshould be used when installing supplementalcoolant additive elements.

The filter inlet and outlet are ordinary .31 in. (7.9 mm) inside diameter rubber hoses.Connect the hoses to obtain the highestpossible coolant pressure differential acrossthe unit. Heater hose connecting points at thecoolant pump inlet and the temperatureregulator housings are recommended. Ifuncertain, plumb the inlet to a point on thedischarge side of the water pump and theoutlet to a point near the water pump inlet.

The outlet should be orificed with an .155 in. (3.9 mm) internal diameter orifice.This will prevent excessive coolant flowthrough the filter which can bypass theradiator core and reduce effectiveness of thecooling system (a .155 in. orifice is a part ofCaterpillar elements). Inlet and outlet linesshould include shutoff valves so the filter canbe serviced without draining the coolingsystem.

The dry charge coolant conditioner isavailable from Caterpillar as an installedoption on the C-10, C-12, and 3406 Engines,and as a not installed option on all truckengines.

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Air-to Air-AfterCooler System

System Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .69Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .69

Chassis Mounted Cooler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .69Ducting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .69Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .69Turbocharger Air Outlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70Clamps and Restraints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70Radiator Shutters/Winter Fronts . . . . . . . . . . . . . . . . . . . . . . . .70

Air-to-Air AfterCooling System Evaluation . . . . . . . . . . . . . . . . . .70General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70Instrumentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70

Pressure GaugesTemperature Measurement

Test Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71Charge Air System Pressure DropAmbient Temperature MeasurementData Processing

69

The function of an Air-to-Air AfterCooledengine cooling system arrangement is toimprove fuel consumption and to loweremissions to meet government regulationsand in some cases permit increased hp. Thesuccess of this cooling system arrangement isdependent on the reduction of engine intakemanifold air temperature. The truck builderwill need to design and supply portions of theassociated componentry into the particularvehicle, similar to other cooling systems.

COOLING SYSTEM DESCRIPTIONThe heated charge air from the engineturbocharger is ducted to a chassis mountedcooler (CMC) which is usually positioned infront of the conventional engine radiator. Thecombined effect of the engine fan and ram airmoves cooling air through the CMC andreduces the charge air temperature. The air isthen ducted to the engine intake manifold.Peculiar to the uniqueness of each truckdesign, the truck builder should note thefollowing design guidelines as applied to thesecomponents:

• Chassis Mounted Cooler (CMC)• Ducting• Connections• Turbocharger Air Outlet• Clamps and Restraints

DESIGN

Chassis Mounted Cooler (CMC) The CMC and ducting system design mustmeet the engine intake air cooling andpressure drop specifications given in theTruck Engine Data Sheets, and packagewithin the space confines of the particularvehicle under consideration. Each CMC unitshould be inspected after manufacture toensure minimal charge air leakage. Forinstance, with the CMC unit sealed andcharged to 30 psi (207 kPa), the pressure dropmust not exceed 4 psi (28 kPa) in 15 seconds.

Baffles of a rubber type material should beprovided around the radiator core to preventengine compartment hot air fromrecirculating through the cores.

DuctingGenerally, the ducting is made from steel oraluminum material and can be from 3 in.(76 mm) to 4.5 in. (114 mm) in diameter. Thesmaller size can be considered if the totalsystem does not exceed the charge airpressure drop limitations listed in the TruckEngine Data Sheet. The ends of the ductingmust be designed to accept the particularconnections selected by the truckmanufacturer. Care must be taken to designducting supports as necessary to preventvibration and premature connection fatigue.

ConnectionsDucting connections must be designed forhigh reliability and durability, and because ofthe relative movement between the engineand CMC there is a need to provide flexibilityin the ducting connections. Usually heatresistant silicon hump type hoses are capableof supplying the needed flexibility for long lifeapplications. Refer to Truck Engine DataSheets for operating temperature andpressure. It is recommended that the hoses besuitable for operation at -40°F (-40°C), andcapable of a proof pressure of 40 psi (277 kPa)at 350°F (177°C) and a minimum burstpressure of 100 psi (689 kPa) at 600°F(316°C). Hoses should also be capable ofwithstanding a negative pressure of 20 in.H20 (5 kPa) to prevent collapse when anengine is being motored downhill. In addition,the hose design must have the capability towithstand flow pressure pulsations and therelative motion of the connecting pipes. Thesehoses must have the integrity not to distortduring engine operation. Care must be takento ensure that all connections remain tight toprevent loss of air boost pressure which wouldcause a loss of power and increase fuelconsumption, and dirt entry which couldcause premature engine wear-out.

70

Turbocharger Air OutletA selection of turbocharger outlet elbows areavailable from Caterpillar for adapting tomost 3406, C-10, C-12, and 3306 Engineinstallations. However, the truckmanufacturer may choose to provide thiselbow for compatibility with a specific truckinstallation. Any new elbow design must beanalyzed and approved by Caterpillar todetermine that forces imposed on theturbocharger are acceptable. Pressure tap P1must be located as illustrated in Figure 7 andat right angle to the bend of the elbow. The3116, 3126, and 3126B Engine have a hosetype connection directly on the turbochargercompressor outlet.

Clamps and RestraintsDepending on the connections selected, theclamping devices must be capable of a highintegrity seal for long life applications, andpreventing ducting separation. It isrecommended that a double clamping ofhump connecting hoses be coupled withbeaded ends on duct tubing. Clamps shouldbe of the constant torque (spring) type tomaintain a seal even with creep of hoseconnection material over time. Mechanicaldevices may need to be devised if the chargeair system geometry is not satisfactory toprevent duct separation.

Radiator Shutters/Winter Fronts To maximize the fuel economy potential withan air-to-air cooling system, the use ofradiator shutters or winter fronts isdiscouraged.

However, if extreme cold climates demand theuse of winter fronts, the winter front musthave a permanent opening of at least 120 in2

(77,419 mm2). Shutter control systems mustbe developed so that the maximumtemperature of the air to the intake manifoldnever exceeds 195°F (91°C). It should also bedemonstrated that in the event that theradiator shutters malfunction, the enginecoolant system reaches overheat conditionbefore the charge air system. In some cases anadditional intake manifold air temperaturecontrol or warning sensor may be required.

AIR-TO-AIR AFTERCOOLING SYSTEM EVALUATION

GeneralThe performance of the total Air-to-AirAfterCooling system must be tested toconfirm that the specifications for theparticular engine and rating are satisfied. Airto air system specifications are shown on theTruck Engine Data Sheet.

The procurement of data to evaluate the Air-to-Air AfterCooling system can beobtained in conjunction with testing toestablish the ambient capability of theradiator cooling system. The followingadditional instrumentation will be required toevaluate the Air-to-Air AfterCooling system.

Instrumentation RequiredPressure GaugesPressure gauges or a manometer, are neededto measure the pressure drop across thoseAir-to-Air AfterCooling components suppliedby the truck manufacturer. Tapped holes (P1 and P2) for the measurement of thepressure drop are provided in the engine’sturbocharger compressor outlet elbow whenprovided and the engine intake manifold asillustrated in Figure 7. Proper location forpressure taps are identified on the generaldimension drawings.

Temperature Measurement(See Figure 7)T1 Ambient temperature thermocouple.

T2 An averaging grid of thermocouples for the measurement of cooling air temperature into the charge air cooler. Spread the averaging grid of thermocouples across the face of the charge air cooler. The individual thermocouple sensor tips should not touch the surface of the charge air cooler.

T3 Temperature of combustion air to engine turbocharger compressor (tap location supplied by truck manufacturer).

71

T4 Temperature of combustion air from the turbocharger compressor. The tap that is provided for the measurement of the compressor pressure (P1) can be jointly used for this temperature measurement with the use of a tee. However, the temperature probe must be long enough to be in the air stream.

T5 Temperature of combustion air in the engine intake manifold. The tap that is provided for the measurement of inlet manifold pressure (P2) can be jointly used for this temperature measurement with the use of a tee.

Test Procedure As stated previously, the Air-to-AirAfterCooling system can be evaluated inconjunction with the testing to establish theambient capability of the cooling systemcomponents to cool the engine coolant withsome exceptions. The Air-to-Air AfterCoolingsystem is to be qualified at 77°F (25°C)ambient and 30 mph (48 km/hr) ram air incontrast to the 110°F (43°C) ambient and

15 mph (25 (km/hr) ram air used to qualifythe engine coolant cooling system. The engineis loaded at “Evaluation” speed and hp duringboth of these tests. There is no need toevaluate the Air-to-Air AfterCooling systemat the engine’s peak torque rating.

Charge Air System Pressure Drop Record pressure measurements at the twolocations indicated in Figure 7. On the 3406C,3406E, and 3306C Engines it is not possibleto get a true static pressure measurement atthe turbocharger outlet P1 due to theturbulence of the air at this point. Test dataindicates that 0.3 in. Hg should be subtractedfrom the pressure measurement taken atpoint P1 to make this a true reading on theseengines only. The corrected pressuremeasurement at point P1 (measurementpressure -0.3 in. Hg) minus the pressuremeasured in the engine intake manifold pointP2 is the total pressure drop of the charge airsystem. This pressure drop must not exceedthe value given on the Truck Engine DataSheet.

Cold Charge Air SystemAir-to-Air

Figure 7

72

Ambient Temperature MeasurementTemperature measurements should berecorded at the locations indicated inFigure 7. The test must be performedwith 30 mph (48 km/hr) ram air.

The ambient air temperature (T1) is one ofthe most important values recorded duringthe cooling system evaluation. As a guidelinefor the measurement of the ambient airtemperature, it is recommended that athermocouple be placed 3 to 5 ft (.9 to 1.5 m) directly ahead and mid center of the truck grill. Engineering judgment,particular to each test environment, mayrequire modifications to these guidelines.

Data Processing If the test ambient (T1) is not at theprescribed 77°F (25°C) or the turbo air outlettemperature (T4) does not agree with thatstated in the Truck Engine Data Sheets, the following formulas should be appliedto the data.

e = T4 - T5 (Aftercooler effectiveness)T4 - T2

T4c = T4 (spec.) + T3 - T1 (See Note A)

T2c = 77 + (T2 - T1) (See Note B)

T5c = T4c - e(T4c - T2c) (See Note C)

C indicates corrected value

Note AT4 (spec.) is the value stated for theturbocharger air outlet temperature foundin the Truck Engine Data Sheets.

Note BThis equation corrects fan recirculationand/or heat exchanger cores located in frontof the air to air core.

Note CT5c is the corrected intake manifoldtemperature expected when the ambient (T1)is at the required 77°F. The corrected intakemanifold temperature (T5c) of an acceptableair-to-air system must not be greater thanthat shown in the Truck Engine Data Sheetsfor the specified hp rating.

Note DThe maximum recommended temperaturerise from ambient (T1) to the turbochargerinlet (T3) is 20°F (11°C).

73

Starting System

General ...........................................................................................74Batteries..........................................................................................75Charging System............................................................................75

Speed Versus Output Characteristics .........................................75Sizing............................................................................................75

Starting System Wiring...................................................................75Proper Grounding of Electrical System..........................................77Starting Aids....................................................................................78

Ether Aids.....................................................................................78Intake Manifold Heaters...............................................................78

74

GENERALA truck engine starting system must be able tocrank the engine at sufficient speed for fuelcombustion to begin normal firing and keepthe engine running. This requires adequatebattery capacity, a starting motor and cablesconnecting battery and motor. The followingmust be observed in order to obtain asatisfactory installation:

• Electric starters must be 12 or 24 volt DCand use a positive engagement pinion drive;i.e., the pinion is engaged with the flywheelring gear before the motor begins to turn. Air or hydraulic starters may also be used.

• Choose between 12 or 24 volt systems withappropriate battery capacity to start theengine at the lowest expected ambientstarting temperature.Use recommendations shown in the tablebelow or the Truck Engine Data Sheet.

• Provide for use of starting aids as indicatedwhen starting temperatures fall below levelsshown in the table below.

Starting Aids

ExpectedColdest

Temperature

Above 20°F(-7°C)

20 to 0°F(-7 to -18°C)

0 to -20°F(-18 to -28°C)

-20 to -40°F(-28 to -40°C)

Below -40°F 4(-40°C)

Ether 2, 3

Aid

Available

AvailableAvailable

Recom’d

Recom’d

Required

Block Heater

Available

AvailableAvailable

Required

Required

Required

LargerAlt/Battery

Available

Available

Recom’d

Required

Required

Intake 1, 2, 3

Air Heater

Available

Available

Recom’d

Recom’d

Required

1 Standard on 3116, 3126, 3126B, and 3306 Engines. Not available from factory on C-10, C-12 Engines.2 Intake air heater a preferred option on 3406B/C Engines.3 Do not use ether aid and intake heater together. Refer to topic Intake Air Heater/Ether Start System in this publication.4 Consult Factory

75

BATTERIESSee the One Safe Source catalog forspecifications of batteries obtainable fromCaterpillar.

The number of batteries in a 12 volt systemmust not be reduced from the number ofbatteries in its 24 volt counterpart. To achievethe 12 volt CCA at °F ratings shown on theTruck Engine Data Sheet, use four 6 voltbatteries in a series-parallel or two 12 voltbatteries in parallel. Batteryrecommendations are based on the use ofrecommended oil viscosity. Below –10°F(–23°C) it may be necessary to warm theengine oil to reduce engine cranking effortand allow oil to circulate more freely.

Nearly all U.S. highway trucks are currentlyequipped with electrical components of 12 volt capacity. To achieve slightly higherstarting motor efficiency and a more favorablepower loss ratio in the starting motor cables,a 24 volt starter motor is used in someinstallations.

CHARGING SYSTEMA variety of alternators are available fromCaterpillar and electric componentsmanufacturers. Caterpillar Truck Enginescan be supplied with brackets that allow useof different makes and sizes of alternators.

When choosing an alternator, consider theseoperating factors:

Speed Versus Output CharacteristicsAlternators are available with markedlydiffering performance curves. By knowing thevehicle application, such as pickup anddelivery or line haul, an alternator and driveratio can be selected to cover the anticipatedengine speed range.

Sizing If the engine speed range, alternatorperformance curve, and alternator drive ratioare correctly selected, abnormal discharges ofthe battery will not occur and an oversizealternator to give extra recharge rate will notbe required. For any service, the maximumelectrical rating (size) of the alternator shouldbe at least 25% greater than the maximumconnected continuous load. Use accessorymanufacturers' data to determine currentdraw of such items as heater and airconditioner blowers, solenoids, radios, lights,instruments, electronic engine controls, etc.

STARTING SYSTEM WIRINGPower carrying capability and serviceabilityare the primary concerns of the wiringsystem.

Select starter and battery cable size from thesize/length table. For correct starting systemcomponents, see wiring diagrams – Figures 8and 9. The wiring should be protected byfuses or a circuit breaker (not shown on thewiring diagrams). They should have sufficientcapacity and be readily accessible for service.

Other preferred wiring practices are:

• Minimum number of connections, especiallywith battery cables.

• Positive mechanical connections.• Permanently labeled or color-coded wires.• Short cables to minimize voltage drop.• Ground cable from battery to starter is

preferred. Current path should not includehigh resistance points such as bolted orriveted joints.

76

Basic Electrical System for 12 Volt Start

Figure 9

Figure 8

Basic Electrical System for 24 Volt Start

77

PROPER GROUNDING OFELECTRICAL SYSTEMSee Figures 8 and 9 (on page 76) for basicelectrical systems with proper grounding.

Proper grounding for vehicle and engineelectrical systems is necessary for properperformance and reliability. Impropergrounding results in unreliable electricalcircuit paths. Stray electrical currents candamage main bearings, crankshaft journalsurfaces, and aluminum components. Theycan also cause electrical noise. These problemsare often very difficult to diagnose and repair.

All ground paths must be capable of carryingany conceivable fault currents. An AWG #4 orlarger cable is recommended between theengine ground and the frame or starternegative post. AWG #4 wire is recommendedto handle alternator currents. A maximum ofthree ring terminals are to be connected to theengine ground to insure ground connectionintegrity. Caterpillar recommends splicing likesize wires together as a method of reducingring terminal congestion.

A bad electrical ground in the charging circuitcan cause a ground through the coolant andthe inhibitor can become electrically charged.This can result in erosion/corrosion,particularly of aluminum components in thecooling system. A voltage check should bemade between the battery negative post andthe coolant. This check should be repeatedwith the entire truck electrical system off,with the engine cranking, and with the engineand all electrical systems operating. Avoltmeter indication of 0 to 0.3 volts is normal.If the voltmeter indication is more than 0.5volts, the source of the problem should belocated and corrected.

To insure proper functioning of the vehicle andengine electrical systems, there must be adirect wire path from the engine ground to thebattery negative post. Caterpillar prefers thisconnection route through the starter negativepost.

A connection routed to a main frame ground,can also be made if the following guidelinesare followed:• Connections to the frame must not be made

with star washers. Star washers should notbe counted on to remove paint from paintedsurfaces. Use flat washers for thisconnection, with the paint completelyremoved in this area.

• Any paint must be completely removedfrom the frame rail at the point where the -Battery connection is made. Failure to doso reduces the effectiveness of theconnection.

• The ground path is not made through framecross members. Bolted connections of framecross members may not always providerequired continuity for this criticalconnection.

• Conductive grease or other methods used toreduce/eliminate the affect of corrosion onthe frame rail connection.

Caterpillar does not recommend a connectionfrom the engine ground to the main frame railat a connection point different than where the-Battery connection is made. A two-pointframe rail connection method depends onframe rail connections. Manufacturing processcontrol of frame rail connections is difficult tocontrol. This multiple frame rail connectionscheme is also more difficult to troubleshoot.

Some engines have a ground stud to facilitategrounding.

Starting motor circuit resistance will beaffected by cable size and length, the numberof connections in the system, the extent andmethod of using the vehicle frame as part ofthe circuit and the possible presence ofadditional contactors in the circuit.

Light duty starting system recommendationfor maximum starting system resistance is atotal resistance effect of 0.12 volts drop per100 amperes for 12 volt systems and 0.20volts drop per 100 amps for 24 volt systems.Maximum total cable lengths which wouldmeet the above criteria when the remainderof the system has a minimum resistance are:(For example the vehicle frame is not used aspart of the circuit.)

A total resistance effect of .075 volts drop per100 amperes should be considered moredesirable for a heavy-duty 12 volt applicationtypical of highway trucks and where moreallowance for maximums in the remainder ofsystem resistance is provided. Maximumrecommended total cable lengths for thiscriteria are as follows:

STARTING AIDSStart aids are recommended (and needed)when temperatures fall below levels asshown in the table on page 74. Glow plugs,intake manifold heaters, and/or ether startingaids are sufficient for most conditions with oiland coolant heating necessary in extremelylow ambients (refer to Operations andMaintenance Management for further dataon cold weather procedures).

Ether AidsEther aids control the injection of ether intothe engine air intake to begin and sustaincombustion until the engine is running(idling) normally. These aids are available asa Caterpillar option for some truck engines.

Proper installation is important to avoidinjecting an excessive amount of ether intothe engine. For ether aids that inject ameasured amount, a maximum of 2.25cc pershot is recommended. For continuous flowtype aids an ether concentration range of 30-80 parts per million by volume isrecommended.

Intake Manifold HeatersIntake manifold heaters are used onCaterpillar 3306C and 3406C Truck Engines.This device uses a heating element mountedin the intake airstream, which ignites asmall volume of diesel fuel, thereby heatingthe air entering the intake manifold. Thisimproves the engine starting ability at lowtemperatures. By maintaining the flame fora predetermined duration after engine start,the engine warms up more quickly,minimizing the white smoke sometimesproduced at start-up.

Note: This device must not be used with othertypes of starting aids such as ether. Such usecan result in explosions and personal injury.

The major components in the system includea heater plug, electronic control unit (ECU),fuel solenoid valve, temperature sensor, andoil pressure switch. An indicator light isneeded on the dash to show the status of thesystem. Two decals warning against the use ofether are included with the engine, one to beplaced near the air inlet (where starter fluidwould normally be introduced) and one to beplaced near the indicator light on the dash.A third decal is included with the engine forplacement on the driver side sun visor orother suitable location, providing instructionson the operation of the air inlet heatersystem.

Cable Size

Maximum TotalCable Length

24 Volt

00

000

0000

9 ft

12 ft

15 ft

Cable Size

0

00

000

0000

_

14 ft

18 ft

22 ft

18 ft

23 ft

29 ft

37 ft

12 Volt 24 VoltMaximum Total Cable Length

78

79

The fuel solenoid valve is factory installed inthe return to tank fuel line and mounted to abracket on the engine (see Figure 10 below).The valve is controlled by the ECU to allowfuel flow to the heater plug after it has beenpreheated, up to the preprogrammed burnduration. The coolant temperature sensor isfactory installed and allows the system to beactivated when coolant temperature is below64°F. The oil pressure switch is factoryinstalled in the oil gallery and is used toprovide a signal to the ECU that the enginehas started.

The heater plug must be installed in the airintake elbow, as close to vertical as possible.Mount the ECU in the cab unless it isenvironmentally sealed. If the ECU ismounted under the hood, it must be mounted

with the wire connections pointing downwardto minimize the chance for water entry. TheECU cannot be mounted on the engine.

A wiring harness diagram for the heatersystem is shown in the Truck InstallationDrawings book. Note that a 50 amp fuse mustbe used between the ECU and starter (30 amp for 24V systems), and a 4 to 8 ampfuse is used between the ECU and theignition switch. A 10 amp fuse is provided inthe factory installed harness to protect the oilpressure switch. Refer to the wiring diagramfor recommended wire sizes for each circuit.An installation kit is available fromCaterpillar which provides the indicatorlamp, 50 amp fuse holder, and OEM interfaceconnector hardware, as well as weld boss forthe flame plug installation.

Figure 10

Direction of fuel flow after installation of fuel solenoidvalve, braided fuel line and heater plug:1. Fuel Tank2. Fuel Transfer Pump3. Secondary Fuel Filter4. Injection Pump5. Injection Nozzle6. Braided Fuel Line7. Fuel Solenoid Valve8. Heater Plug

80

Governor and Controls (Mechanically Governed Engines)

Governor .........................................................................................81Governor Control ............................................................................81

Shaft Movement and Forces .......................................................81Linkage.........................................................................................81

Lever-Link SystemsShielded Cable Systems

Soft Links .....................................................................................81Starting System Wiring...................................................................81Energized-to-Shutoff Solenoid .......................................................82Energized-to-Run Solenoid ........................................................82Shutoff Shaft ...................................................................................82Return Springs................................................................................82Federal Legislation (FMVSS 124)..................................................82Air-Fuel Ratio Control .....................................................................82

81

GOVERNORDiesel engines require a governor systemsince the fuel is injected directly into thecombustion chamber. All mechanicallygoverned Caterpillar Truck Engines have full-range governors. To control vehicle speed, thetruck driver or vehicle operator works directlywith the governor spring compression. Stopsin the governor are set for engine low idle rpmand high idle rpm. Flyweights govern theengine rpm by controlling fuel deliverythereby maintaining the selected enginespeed. In addition to low idle and high idlerpm, the governor and its relatedattachments provide or control the followingfunctions:

• Full load power (rack or sleeve setting).• Torque rise (torque spring and spacer).• Acceleration smoke (fuel ratio control).• Engine shutoff.

GOVERNOR CONTROLDepending on engine model, the enginegovernor on Caterpillar inline truck enginesis located on either left or right side. Theengine is usually supplied with governorcontrol linkage to the left side of the enginewhen that engine has a right-side-mountedgovernor. For application consult the TruckEngine Installation Drawing book.

Shaft Movement and Force See Installation Data Section for travel andforce values.

Linkage Engine to Foot PedalLever-Link Systems Lever-link systems are most commonly used.It is also a very commonly misadjustedsystem. To minimize complaints of excessivehigh idle pedal forces, the lever-link piecesshould be adjusted to give best mechanicaladvantage at high idle. See example:

Succeeding links and levers which proceedtowards the operator should be alternatelyarranged - right angle and then past rightangle until the foot pedal is reached.

Shielded Cable Systems Shielded cable or push-pull cable designs aresometimes used as governor control linkage.This type of system has one importantadvantage over the lever-link systems - it willisolate the governor terminal lever from truckcab motion. This feature becomes importantas cab mountings and engine mountingsbecome more resilient and, therefore, relativemotion between the engine and truck cabbecomes greater. A mechanism should beincluded to insure proper adjustment for fullgovernor shaft travel.

Soft LinksTo minimize the possibility of damage to thegovernor or governor linkage when contactingthe high idle stop, a spring link or spring-loaded broken lever is used. It is suppliedwith the truck engine arrangement.

STARTING SYSTEM WIRINGThree types of engine shutoffs are availablefor Caterpillar Engines. In some casesmultiple shutoffs can be supplied withan engine.

Figure 11

Example

82

ENERGIZED-TO-SHUTOFF SOLENOIDThe energized-to-shutoff solenoid is mountedon the governor shutoff housing. It is usuallyactivated by an instrument panel mountedswitch or the key starter switch. The solenoidcontains a single coil for pull-in and hold.Consult Caterpillar for voltage and currentdemand for a particular engine.

ENERGIZED-TO-RUN SOLENOIDAll engines are normally equipped with anenergized-to-run shutoff solenoid. It isnormally key switch activated. The shutoffsolenoid circuit should be a dedicated circuitwith no additional accessories or trucksystems wired into it. This circuit should beprotected with a slow blow fuse. ConsultCaterpillar for voltage and current demand.

SHUTOFF SHAFTThis shaft extends from the governor shutoffhousing of the scroll-type fuel system. Toutilize this shaft, a separate linkage system(usually a push-pull cable) must be provided.The shaft must be held in shutoff positionuntil the engine stops. Consult the TruckEngine Installation Drawing book formechanical shaft rotation degrees.

RETURN SPRINGSWith the advent of Federal legislation, suchas FMVSS 124, requiring “dual energy”return springs, the possibility of excess pedalforce complaints becomes greater. Tominimize this possibility, since governor shaft

holding torque increases with engine rpm, thereturn spring attachment geometry should besuch that maximum spring return torque isapplied at low idle and minimum returntorque is applied at high idle.

FEDERAL LEGISLATION (FMVSS 124)This standard establishes requirements forthe return of a vehicle’s throttle to the idleposition when the driver removes theactivating force from the accelerator control,or in the event of a severance or disconnectionin the accelerator system. Even though thisregulation is not complex and has had fewrevisions during the formative period,Caterpillar disclaims any responsibilitytowards interpretation of this document.

Caterpillar supplies “throttle linkage” forengines with a right side mounted fuelsystem. Since this is a partial system, itcannot in itself be certified as meeting therequirements in FMVSS 124.

AIR-FUEL RATIO CONTROLA governor-mounted air-fuel ratio control issupplied with most turbocharged CaterpillarTruck Engines. This device prevents theinjection of excessive amounts of fuel (thatwill be sent out the exhaust pipe as blacksmoke) during periods of engine acceleration.The device also senses engine inlet manifoldpressure and is active only during periods oflow boost. As the turbocharger reaches fullrpm and delivers sufficient air, the controlbecomes inactive.

83

Support System

General Requirements ...................................................................84Three-Point Mounting ..................................................................84Acceptable Isolation.....................................................................84Acceptable Flywheel Housing Bending Moment ........................84

Three-Point Mounting.....................................................................84Trunnion Mount............................................................................84Bracket Mount..............................................................................84

Designing for Vibration Isolation.....................................................84Initial Mount Selection..................................................................84Data Required..............................................................................84Prepare Data................................................................................84Complete Calculations.................................................................85Analyze Results ...........................................................................85Repeat Dynamic Analysis ...........................................................85

Flywheel Housing Bending Moment ..............................................85Allowance for Motion ......................................................................87Off-Highway Trucks ........................................................................87Truck Vibration Review...................................................................87

84

GENERAL REQUIREMENTSTo satisfy Caterpillar guidelines for anacceptable engine installation, the followingrequirements must be met.

Three-Point MountingThis system resiliently supports the engine ata single point at the front (minimal torsionalrestraint) and at two points (each side) on theflywheel housing or transmission. The result,normally, is a system capable of efficientlyallowing the large amounts of truck frametorsional deflection without imparting unduestresses to the mounting pieces of the enginestructure.

Acceptable IsolationEngine mounts must provide acceptableisolation of engine excitation forces from thetruck frame and cab.

Acceptable Flywheel Housing Bending MomentThe engine must be installed so that thesimple beam static bending moment at theflywheel housing/transmission joint does notexceed the maximum value given in the TruckEngine Data Sheet for a particular engine.Transmissions creating an overhung momentlarger than the maximum recommended musthave additional support.

THREE-POINT MOUNTINGTwo types of front supports are used withCaterpillar engines.

Trunnion MountSome engines are equipped with a front coverwhich has a nose or cylindrical extension. Anon-metalic sleeve can be clamped onto thenose of this extension. This arrangementallows engine rotation about the crankshaftcenterline. Rear mounts must be providedwhich adequately locate the engine fore andaft and transmit torque reaction to the vehicleframe.

Bracket MountSome engines are equipped only with amounting face; others with a rigid bracket offthe front cover face. This provision allowsmore freedom in designing for a desired rollcenter or mounting stiffness.

See the General Dimension drawing fordesign details on a particular engine.

DESIGNING FOR VIBRATION ISOLATIONThe following iterative process outlines theprocedure for selecting engine mounts toachieve acceptable isolation.

Initial Mount SelectionWork with mount manufacturers to select aseries of mounts that:

• Will fit into the available space.• Will have adequate fatigue life based upon

the expected torque and acceleration loads.

Data Required • Engine weight and mass movements of

inertia about its center of gravity.• Transmission weight and mass movements

of inertia about its center of gravity (includeclutch weight).

• Location and number of engine mounts (andtransmission mounts if equipped).

• Space available for mounts.• Spring rates in three perpendicular

directions for initial mount selection.• Approximate frame stiffness (to compare to

isolator stiffness).

Prepare Data• Calculate combined center of gravity of

engine/transmission package.• Calculate mass moments of inertia for

engine/transmission package.

85

Complete CalculationsAnalyze the engine/transmission package as arigid mass supported by the isolators; i.e., a 6 degree of freedom model. This computationis best handled with the aid of a computer.The mounting analysis is called normalmodes and is available on most of the majorFinite Element Programs. In addition,smaller software packages should be availableto calculate natural frequencies and modeshapes for six degree of freedom models.

Analyze ResultsOutput of the calculations will be six naturalfrequencies and their associated mode shapes.Construct an interference diagram todetermine if objectionable resonances occurin the operating speed range.

In general, the following design guidelinesshould be followed:

• First order pitch and vertical moderesonance should occur below the peaktorque speed, but should be greater than 10-12 Hz to avoid vehicle system modeswhich can be excited by road induced loads.

• Firing frequency roll mode resonance shouldoccur at a speed less than 1/3 of engine idle(approximately). For an in-line 6 cylinderengine, the resulting third order modewould be below 10 Hz.

Note: Vibration order =Vibration Frequency (cpm)

Engine Speed (rpm)

• Mount stiffness should be much less thanthe frame stiffness (approaching a factor of 1/10).

• Remember that placement of the mountsaffects the engine mounting natural frequencies; e.g. spreading mounts laterally will increase the roll mode natural frequency, while increasing the distance between the front and rear mounts increases the pitch and yaw mode natural frequencies, etc.

Repeat Dynamic AnalysisAnalyze several candidate mounts to obtainacceptable isolation.

FLYWHEEL HOUSING BENDING MOMENTThe maximum bending moment that canbe tolerated at the flywheel housingtransmission joint is given on the TruckEngine Data Sheet. For determination ofbending moment for overhung transmissioninstallations, see Figure 12.

86

To compensate for transmissions which createa high bending moment due to overhung load,a third mount is sometimes installed. Properdesign of the support is essential. Forces anddeflections of all components of the mountingsystem should be resolved. If the third mountis in the form of a spring with a vertical rateconsiderably lower than vertical rate of therear engine support, the effect of the mount isin a proper direction to reduce bending forceson the flywheel housing due to downwardgravity forces, but the overall effect may beminor at high gravity force levels. The use ofsupports with a vertical rate higher than theengine rear mount is not recommended sinceframe bending deflections can subject the

engine/transmission structure to high forces.Another precaution is to design the support sothat it provides as little resistance as possibleto engine roll. This helps to isolate theengine/transmission structure from truckframe torsional deflection.

For engine mount reaction calculations whenusing a transmission support, see Figure 12.

Certain transmissions provide mounting padswhich can be utilized to support the rear ofthe engine. Using this mount is desirablesince the transmission overhung mass may beenough so that a transmission support is notneeded.

Determination of Bending Moment for OverhungTransmission Installation

Figure 12

MX = WT L1

For Static Bending Moment Calculation forTransmission Support Installation use:

MX = WT L1_ FL2

MX = Static Bending Moment at FlywheelHousing/Transmission

L1 = Transmission CG Location

WT = Weight of Transmission _ Complete with Oil

F = Rear Support Lift

L2 = Rear Support Location

87

ALLOWANCE FOR MOTIONWith the mountings now needed to satisfynoise and vibration requirements, enginemovement has increased. To preventinterference or fatigue failure, provide flexiblesections in the exhaust piping, air intakepiping, air compressor line, fuel lines andradiator hoses. Sheet metal and frameclearances must be sufficient to allow for bothrelative movement and manufacturingtolerances.

Also consider engine movement in the designof fan tip clearance with fan shroud andthrottle linkage. The clutch linkage must bearranged so that engine roll will notdisengage the clutch.

OFF-HIGHWAY TRUCKSThe mounting system for trucks intended foroff-highway service should receive extra care.Not only will the system be subjected to highgravity force loadings, but the off-highwayapplication will cause extra amounts of

vehicle-frame torsional deflections, and theengine mounts will need to resist largeramounts of torque reaction due to highnumerical drive line reduction in low creepergear.

TRUCK VIBRATION REVIEWThe analysis procedure for selecting enginemounts outlined in the previous paragraphsassumes a rigid truck frame. Utilizing thisanalysis method will normally produce anacceptable engine mounting system. However,the engine resting on the mounts representsjust a portion of a larger dynamic systemknown as the truck. In the following figure itcan be seen that a truck is made up of severalcomponents that contribute to its dynamicresponse and to what the operator feelsduring operation.

To complete a vibration review, the dynamicresponse of the truck system must bedetermined through testing.

Figure 13

Vehicle Spring-Mass System

88

Alignment and Torsionals

Alignment ........................................................................................89Torsionals........................................................................................89Engine Damper...............................................................................89

89

ALIGNMENTDue to the standardization of automotivepowertrain components, very few, if any,alignment problems are encountered. Whensuch problems do occur, they usually resultfrom an inadequate engine support systemor manufacturing errors.

Prior to final engine-transmissioninstallation, detailed alignment proceduresshould be obtained from the respective clutchand transmission manufacturers.

Mis-alignment can lead to premature enginecrankshaft or driveline component failure.

TORSIONALSStandardization and broad usage ofdrivetrain components minimizes thepossibilities of torsional problems. Regardlessof this, always check with the factory whenusing a new transmission to be sure thetorsionals have been checked.

ENGINE DAMPERThe front of the crankshaft in all CaterpillarTruck Engines is equipped with a torsionaldamper. This damper may be a rubber typeor a viscous type. Whenever a front powertakeoff or automatic transmission is used,a viscous damper is generally required. Thefactory should be consulted for the correctdamper whenever a front power takeoff orautomatic transmission is used.

90

Auxiliary Braking Devices

Retarding Capability .......................................................................91BrakeSaver .....................................................................................91

General Description.....................................................................91Components.................................................................................91Control System ............................................................................92Oil System....................................................................................93Performance and Cooling............................................................94Installation ....................................................................................95BrakeSaver Oil Change Period ...................................................95

Exhaust Brakes...............................................................................96Compression Brakes ......................................................................97

Jacobs Engine Brake...................................................................97Pac Engine Brake........................................................................97

91

* Based on 40 psi at 2400 rpm 1 375 hp & lower**Based on 55 psi at 2800 rpm 2 435 - 550 hp

3 600 hp

RETARDING CAPABILITYThe chart above shows the retardingcapability of the various devices availablefor Caterpillar Truck Engines.

BRAKESAVER

General Description Available as an option on 3400 Family ofTruck Engines, the BrakeSaver hydraulicretarder is an auxiliary braking system forcontrolling or reducing speeds on long gradesor curves when extended or frequentapplication of the service brakes is notdesirable. Unlike other auxiliary brakesystems, the BrakeSaver does not imposeadditional mechanical stresses on the engine.It relies only on hydraulic braking resistancedeveloped by pumping oil against a fixedstator in the flywheel housing and dissipatingthe retarding heat generated through theengine cooling system.

In principle, the BrakeSaver is essentially astalled fluid coupling. Even when engagedwith the vehicle stopped, it will not stall theengine. Since the heat generated by brakingis dissipated by the engine cooling system,normal engine operating temperatures aremaintained on long downhill runs.

The BrakeSaver may be used with otherretarding devices such as Jake Brake or PacBrake. The total braking capability needs tobe reviewed with the driveline componentscapability.

BrakeSaver ComponentsBrakeSaver components shown in Figures 14,15 and 16 include:• Crankshaft mounted rotor running between

two stationary stators - one cast in theflywheel housing and the other bolted to theflywheel housing.

• Flywheel housing mounted stators andassociated seals.

• BrakeSaver control valve, and oil piping.• Driver control systems; manual and

automatic/manual.• Oil cooler and associated piping.Note: Refer to the Truck Engine Data Sheetfor oil capacity and maximum allowable oiltemperature of the engine with a BrakeSaver.

Retarding Horsepower

3208311631263306C3176BC-10C-123406C3406E3406E1

3406E2

3406E3

280028002600260021002100210021002100210021002100

125N/AN/AN/AN/AN/AN/AN/AN/AN/AN/AN/A

N/AN/AN/AN/A160N/AN/AN/AN/AN/AN/AN/A

N/AN/AN/AN/AN/AN/AN/A200200200200200

N/A152139N/AN/AN/AN/AN/AN/AN/AN/AN/A

N/AN/AN/AN/AN/AN/AN/A250N/AN/AN/AN/A

N/AN/AN/AN/A250N/AN/AN/AN/AN/AN/AN/A

N/AN/AN/AN/AN/A290N/AN/AN/AN/AN/AN/A

N/AN/AN/AN/AN/AN/A350N/AN/AN/AN/AN/A



N/AN/AN/AN/AN/AN/AN/AN/A???476399431



N/AN/AN/AN/AN/AN/AN/A380380380380380

EngineModel RPM 26 PSI 40* PSI 50 PSI 55* PSI 70 PSI 336A 310A 312A C346D 349A 340A P36 P37

BrakeSaver

Exhaust Brake Jake Brake PacBrake

Figure 143406 & 3408

92

Control System The manual control system has a handcontrolled air valve which can modulatebraking effort from 25% up to full brakingpower. This system is appropriate for trucksrequiring varied braking effort over anextended period of time.

The automatic/manual system providesautomatic hands off operation in addition tomanual control. This system is advantageousin applications having many engagementsduring a short period of time.

As shown in Figure 15, the BrakeSaver isactivated by compressed air from the normaltruck supply. Air pressure is reduced by thepressure reducing valve to give brakinghorsepower consistent with the engine model.

When the BrakeSaver has a manual controlsystem (optional) or the selector switch of theautomatic/manual system is in the manualposition, the driver selects the desiredbraking effort by moving the operator controlvalve lever.

This directs air through the two-way checkvalve to the BrakeSaver control valve (Figure 17). This valve controls the oil flow tothe BrakeSaver and maintains the selectedbraking effort. Returning the control to theOFF position stops the air supply and airpressure, and the control valve is vented tothe atmosphere to disengage the BrakeSaver.

When the selector switch is in the automaticmode, the BrakeSaver can be activated by theoperator control valve, as in the manualmode, or whenever the accelerator is releasedproviding the clutch is engaged. Thiscompletes an electrical circuit to a solenoidvalve which directs air to the BrakeSavercontrol valve. If either the accelerator or theclutch is depressed, the air supply is blocked.Pressure in the control is then vented to theatmosphere to disengage the BrakeSaver. Theautomatic mode, unlike the manual mode,does not modulate the air pressure and thusprovides full braking capacity whenever theBrakeSaver is engaged.

Figure 15

93

Oil SystemAs seen in Figure 16, the 3406 BrakeSaverEngine has a two-section oil pump. Onesupplies oil to the engine, and the othersupplies oil directly to the control valve. Whencontrol air pressure moves the BrakeSavercontrol valve spool to the right (Figure 17),engine oil flow is directed to the BrakeSaver.With the control valve spool in this position,it takes about two seconds to fill theBrakeSaver and bring its outlet oil pressureto the operating level. The BrakeSaveraverage oil pressure, plus a spring force,opposes air pressure and positions the controlvalve spool to provide the selected rate ofretardation. Heated oil flows from theBrakeSaver through the oil cooler and back tothe control valve. At this point, the oil flow isdivided. A portion goes back to theBrakeSaver to maintain the amount of

braking determined by the position of thecontrol valve spool; the remainder returnsto the engine oil pan.

As engine speed changes, the control valvesenses the change in the BrakeSaver mean oilpressure. It then adjusts the spool tomaintain the selected level of retardingwithin the movement limits of the controlvalve spool.

When the control air pressure is stopped todeactivate the BrakeSaver, the spring forceand BrakeSaver mean oil pressure move thecontrol valve spool to the left, closing theBrakeSaver oil inlet. The rotor then pumps oilfrom the BrakeSaver in less than twoseconds. Except for a small amount of oilnecessary to lubricate the BrakeSaver seals,all engine oil goes through the oil cooler andreturns to the oil pan.

Figure 16

3406 Truck Engine Retarder System

94

Performance and Cooling Total truck retarding horsepower at thewheels is the sum of BrakeSaver engineretarding horsepower divided by drivelineefficiency. BrakeSaver engine retardingperformance is shown on the curve in Figure 18. Expressed as an equation:

Total retarding hp =BrakeSaver engine hpdriveline efficiency

If nominal driveline efficiency for a tandemdrive tractor is 85% and BrakeSaver engineretarding horsepower is 380 Bhp the totalretarding horsepower becomes:

Total retarding hp = 380 = 447 hp.85

A BrakeSaver equipped truck must have acooling system designed to accommodate theheat rejection rate of the BrakeSaver. Theheat rejection of the BrakeSaver isconsiderably higher than the engine heatrejection. The heat rejection of the

BrakeSaver during retarding is 12,780Btu/min (225 kW).

The BrakeSaver retarding capacity isdependent on engine rpm, with maximumcapacity limited by control air pressureoccurring at 2100 rpm engine speed. Brakingeffort thus can be varied by:

• Increasing and decreasing engine rpm.

• Modulating control air pressure.

• Shifting gears to increase or decrease engine speed.

These variables may be used in anycombination to match braking requirementsas long as the following BrakeSaverperformance limits are recognized:

• Maximum retarding occurs at 2100 rpm engine speed and maximum control air pressure.

• BrakeSaver will not bring a vehicle to complete halt. It is a retarder, not a service brake.

Figure 17

95

InstallationThe BrakeSaver increases the length of thestandard 3406 Engine 4.00 in. (101.6 mm).The front and rear support locations are thesame as the standard engine. However,driveshaft alignment and length may needto be modified.

All necessary engine components, including alarger engine mounted oil cooler, are providedwith the BrakeSaver equipped engine. Thefollowing items must be provided by the truckor vehicle manufacturer:

• Control system wiring.

• Control system tubing and fittings.

• Mounting brackets for various valves and clutch switch.

• Mounting for engine oil filter.

The accelerator switch is adjustable for acoasting position. This allows the driver tomaintain a position when the BrakeSaveris OFF and the engine is not being fueled.

The controls should be located so the drivercan operate them without looking away fromthe road.

An installation drawing, containingdimensions and specification installationinstructions for the BrakeSaver is shown inthe Truck Engine Installation Drawing book.

BrakeSaver Oil Change PeriodThe recommended oil change period for theBrakeSaver is the same as for the standardnon-BrakeSaver equipped engine.

Detailed procedures for checking BrakeSaverperformance are contained in the engine’sService Manuals and are available fromCaterpillar Dealer Service Departments.

Figure 18

3406 BrakeSaver Performance

96

EXHAUST BRAKESAuxiliary exhaust braking devices areapproved for use on the 3406, 3116, 3126,3126B, and some 3208T Engines. Themaximum permissible exhaust backpressureat maximum engine braking rpm for thestandard 3406C and 3406E Engines is 50 psi(345 kPa). An optional valve spring packagefor the 3406C will allow 70 psi backpressure.Backpressure for braking is measured at the1/4 NPT hole in the 3406 exhaust manifoldclosest to the turbocharger. There aredifferences in available exhaust brakingdevices from those with little or no leakagewhen activated to those with a great deal ofleakage. Sliding Gate Type exhaust brakesallow minimal leakage and must have a relieforifice to limit the maximum exhaustmanifold backpressure at maximum enginebraking rpm to 50 psi (345 kPa). The orificesize required for a specific 3406C maximumbraking rpm is as follows:

For 3208 T Engines with a steel camshaft androller cam followers, an exhaust brake isapproved with a maximum exhaust

backpressure of 25 psi (172 kPa) at maximumengine braking rpm. All ratings of 240 hp(179 kW) and above have the components asstandard which will permit use of an exhaustbrake. The components are optional from thefactory on the 210 hp (157 kW) and 225 hp(168 kW) @ 2600 rpm ratings. Engines whichhave exhaust brake capability are stampedwith the letters EXBC at the end of the OEMpart number space on the engine informationplate located on the valve cover. Acceptablebraking rpm for all ratings is 2800 rpm. Witha sliding gate type exhaust brake whichallows minimal leakage, a relief orifice asshown below is required for a maximumbackpressure of 25 psi.

The exhaust backpressure must not exceed 25 psi (172 kPa) as measured at the tappedhole commonly provided in the exhaust brake.

.625 (15.9 mm)

.687 (17.4 mm)

.750 (19.8 mm)

180020002200

160190225

Orifice Size MaximumBraking rpm

Approx. Retardinghp @ Maximum

Braking rpm

97

With a Flapper Type exhaust brake, there isusually leakage around the movable plate. Toobtain maximum performance level braking asmaller hole would likely be required. Amethod to size the hole would be as follows:

• Start out with a small hole - approximately 0.33 in. (8 mm).

• Back out any adjusting screw to zero clearance.

• Connect a pressure gauge to the designated location.

• Find a hill or tow the truck and read backpressure at the applicable Maximum Braking rpm by slowly closing the flapper plate. (Ensure that maximum backpressure is not exceeded duringthe test).

• Modify the orifice as necessary to attain maximum backpressure.

The 3116 and 3126 engines have a maximumallowable exhaust backpressure of 55 psi.

The 3126B engine is limited to 40 psi at theexhaust brake with 2400 rpm engine speed.

The 3306C, C-10, and C-12 engines are notpresently approved for operation withexhaust brakes.

COMPRESSION BRAKES

Jacob Engine BrakeThe Jacobs Manufacturing Companymanufactures compression engine brakes,which are specifically designed for use onCaterpillar 3406C, 3406E, C-10, C-12, andthe later built 3306B Engines. The JakeBrake comes complete with all attachingcomponents and in-cab controls needed forinstallation. Certain throttle linkagearrangements, and vehicles equipped withautomatic transmissions, require specialadapter kits. Authorized Jacobsrepresentatives should be contacted todetermine the proper engine brake modeland, if needed, adapter kit for your vehicle.

The 3406E, C-10, and C-12 electronic enginecontrols interface directly with the JakeBrake, eliminating the need for any otherconnections.

Pac Engine BrakeThe PacBrake (P36) works similarly inprinciple to the Jake Brake. However, whencombined with an exhaust brake, thecombination (P37) develops even greaterretarding power.

98

Emmisions Noise and Gaseous

Gaseous Regulations .....................................................................99Nitrous Oxides ...........................................................................100Particulates ................................................................................100Low Sulfur Fuel..........................................................................100

Noise.............................................................................................100

99

GASEOUS REGULATIONSThe chart shown in Figure 19 shows the gaseous regulation changes that have occurred through 1998.

1987 1989 1991 1993 1995 1997 1999 2001

0.25

0.20

0.15

0.10

0.05

0.00

YEAR

Fuel

Sul

fur

- P

erce

nt

1987 1989 1991 1993 1995 1997 1999 2001

0.8

0.6

0.5

0.3

0.1

0

YEAR

NO

x - g

/hp-

hr

1987 1989 1991 1993 1995 1997 1999 2001

0.8

0.6

0.7

0.5

0.4

0.3

0.2

0.1

0

YEAR

Par

ticul

ates

g/h

p-hr

URBAN BUS 0.071994URBAN BUS 0.051996

.1

.25

.6

5

6

4

10.7

.22

.10

.05

U.S. DIESEL EMISSION REGULATIONS

HC = 1.3 CO = 15.5

Figure 19

100

Nitrous OxidesNitrous Oxide (NOx) levels remained at 10.7 gm/hp-h (6509 g/kW-h) through 1989,changed to 6 gm/hp-h (3650 g/kW-h) Jan. 1, 1990 and changed again Jan. 1, 1991to 5 gm/hp-h (3041 g/kW-h). A furtherreduction to 4 gm/hp-h occurred in 1998.

ParticulatesParticulate requirements went into effect Jan. 1, 1988 at 0.6 gm/hp-h (365 g/kW-h) andremained at this level through 1990. On Jan. 1, 1991, the particulate level wasreduced to 0.25 gm/hp-h (152 g/kW-h) andwas further reduced to 0.1 gm/hp-h (61 g/kW-h) Jan. 1, 1994.

Averaging of NOx and Particulate levels ispermitted starting Jan. 1, 1991.

Low Sulfur FuelThe maximum level of sulfur in the fuel usedfor certifying the engine was reduced to .10 percent in 1991. The level was furtherreduced to .05 percent in 1994. No furtherchanges are expected beyond 1994.

No changes are planned for the currenthydrocarbon (HC) level of 1.3 gm/hp-h(791 g/kW-h) or the current carbon monoxide(CO) level of 15.5 gm/hp-h.

NOISEThe 83 dB(A) passby noise level was reducedto 80 dB(A) Jan. 1, 1988 and no furtherchanges are planned.

Optional engine noise treatment is availablefor Caterpillar Truck Engines. Usage of thistreatment is determined by the truck OEM.The chart below shows available noisesuppression hardware.

AvailableNoise Hardware

Engine Model

3208

31163126

3126B 3306C C-10 C-12 3406C 3406E

XXXX

XXX X

X

X

X

X

XXX

XX

X

Block Structural Plate

Noise Panels- RH Block- LH Block- Oil Pan- Valve Cover- Front Cover

101

Serviceability Guidelines

General .........................................................................................102Safety............................................................................................102Tools..............................................................................................102Maintenance Accessibility ............................................................102Fluid Compartments .....................................................................102

Filling..........................................................................................102Draining ....................................................................................102Level Checks ...........................................................................102

Filters ............................................................................................103Air Induction/Exhaust Systems ....................................................103Cooling System ............................................................................103Repair Requirements ...................................................................103

Accessibility ...............................................................................103Adjustment Requirements.........................................................103

102

GENERALThese guidelines apply to Caterpillar TruckEngines installed in on-highway truckchassis, including attachments and auxiliaryequipment.

Accessibility for servicing of truck enginesshould be a major consideration in the designof OEM vehicles with all standard andoptional accessories installed. Give specificattention to OEM accessories, such as airconditioning compressors, alternators, powersteering pumps, radiator supports, and otheritems whose locations may interfere withengine component serviceability.

SAFETYWarning labels must be attached in thevicinity of the cooling fan on vehicles withthermostatically controlled fans. These labelsprovide a warning that the cooling fan maystart at any time that the engine is running.

TOOLSClearance for tools should be sufficient toinsert and remove component mounting bolts.A 90° swing for tools is needed for assemblyand disassembly.

MAINTENANCE ACCESSIBILITY• Engine maintenance functions should be

performed with the engine stopped.• Engine maintenance should be accessible

from ground level.• Access to components from beneath the

vehicle should be avoided.• Frequently maintained points should have

direct accessibility without requiring tools for the removal of guard or cover. The use of quick-disconnect fasteners is encouraged.

• One person should be able to performperiodic maintenance unassisted.

• All routine maintenance and adjustmentsshould be capable of being performed with normally available hand tools or no tools.

• Convenient access to a diagnostic toolconnection port must be provided in theoperator compartment of those vehiclesusing electronically controlled engines.

• Sufficient clearance and wire length mustbe provided to allow electrical connectors tobe decoupled and allow the use of breakouttee’s for troubleshooting.

FLUID COMPARTMENTS

Filling• Fluid compartment fill and checkpoints

should have easy access on the vehicle.• Fluid compartment filler openings should be

vertical whenever possible.• Filler openings should be located to prevent

debris or dirt from falling into compartmentduring filling.

• The filler opening should be large enoughto accept normally used nozzles and hoses.

Draining• Should be accessible with all accessories

in place.• Fluid drainage should not contact vehicle

and should have direct access to collectionin container.

Level Checks• Dipsticks used to check different fluids (for

example, engine oil and transmission fluid)should not be interchangeable.

• Dipsticks should seal tightly when installedin their guide tubes.

• Fluid level should indicate proper level withvehicle parked on level surface.

• To eliminate false readings from oil drain inguide tube, the dipstick should beterminated shortly below the low oil mark.

103

FILTERS• Adequate clearance should be provided for

tightening and removal.• Drainage should not contact vehicle when

filter is being changed and should havedirect access to collection container withoutspillage.

• Remote-mounted filters should be located onvehicle where dirt and trash do notaccumulate to avoid contaminating thesystem when opened.

• Filters should be mounted away from roadsplash and water runoff areas.

• Fuel filters and water separators should bemounted in a location which minimizeschances of freezing or wax formation.

AIR INDUCTION/EXHAUST SYSTEMS• Air cleaners should be mounted away from

road splash and water runoff areas.• Routing of air induction or exhaust piping

should not block service or adjustmentpoints.

• Removal of air and exhaust piping shouldbe easy to facilitate component removal.

COOLING SYSTEM• Routing of hoses between engine and

radiator should provide maximumaccessibility to service and adjustmentpoints.

• Removing coolant hoses and lines, whichnecessitates draining the system to accesscomponents and make minor repairs, isundesirable.

• Coolant fill and level check locations shouldbe readily accessible.

• Coolant system drains should be located sodrain or splash does not fall on other vehiclecomponents.

REPAIR REQUIREMENTS

Accessibility• Removal and installation of major

components should be from top or side ofvehicle. If it is necessary to removecomponents from bottom, adequateclearance should be provided without theneed to lift the vehicle.

• Installation and removal of componentsshould be with minimum disturbance ofother components.

• Accessibility for service tools to removecomponents, including jacks, presses andpullers, should be provided.

• Clearance should be provided for access to lifting points.

Adjustment Requirements• Operating adjustments should be able to be

made on vehicle without removing adjacentcomponents. Example: fan belt adjustment.

• Maintenance and adjustment locationsshould be accessible without contacting hotcomponents and exhaust piping, or the hotsurface should be shielded.

• Service personnel should not be exposed tounstable or uncomfortable positions whenservicing or removing components.

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