Tomorrow's Tech, August 2014

� PUMP 'N TANKS � DRILLED OR SLOTTED ROTORS? � CHRYSLER V6 SERVICE

August 2014TomorrowsTechnician.com

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REAL WORLD......................................12Converting the MassesOmar Trinidad and Ralph Tate, associate professors at Southern Illinois University, provide details on a gasoline-to-electric vehicle conversion on a 2001 Chrysler PT Cruiser. Discover what they did to create a battery-powered electric vehicle.

ENGINE SERIES.................................16Keeping the 3.5 AliveIf ever there was a service opportunity ripe for the taking,Chrysler’s 3.5L SOHC V6 engine (and its 2.7L, 3.2L and4.0L cousins) is it. This engine was introduced back in 1993as an “upgrade” from the earlier 3.3L pushrod V6 engine.Find out what it takes to keep these engines running smooth.

UNDER COVER..................................36The Hubbub on Undercar NoisesTech writer Gary Goms discusses how to diagnose noise, vibration and harshness (NVH) complaints in worn drivetrain components like universal joints, CV joints orwheel hub assemblies. Also, we take a look at Slotted vs. Drilled rotors.

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Career Corner: Job Search Tips 4

Finish Line: 2014 Ford/AAA Auto Skills 8

Service Advisor: Fuel System Service 28

Under the Hood: A/C System Diagnostics 46

Tech Tips Engine Compression Tests 50

TT Crossword 52

TT Classifieds 54

Report Card: Jeep Dakar Concept 56

Tomorrow’s Technician (ISSN 1539-9532)(August 2014, Volume 13, Issue 5): Published eight times a year by Babcox Media, 3550 Embassy Parkway, Akron, OH44333 U.S.A. Complimentary subscriptions are available to qualified students and educators located at NATEF-certifiedautomotive training institutions. Paid subscriptions are available for all others. Contact us at (330) 670-1234 to speak toa subscription services representative or FAX us at (330) 670-5335.

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EDITORIAL STAFF:


Airtex Fuel Delivery Systems LaunchesPUMP•ED Educational ProgramAirtex Fuel DeliverySystems is introducing anew pilot programfocused on educatingfuture technicians in theautomotive industry. TheAirtex PUMP•ED programwill train student techni-cians across the country in the areas of fuel systemdiagnostics and fuel pump installations. Set to kick off in the fall of 2014, the Airtex PUMP•ED

program will include selected technical schools and uni-versities across the country. Airtex will send its ASE certified technicians to class-

rooms to provide the most up-to-date information abouttoday’s complex fuel systems. The technicians will showstudents the steps to make the right fuel system diagnosis, technical tips to avoid difficulty during repairwork, and how to follow through to successful fuel pumpinstallations. As a part of the program, each technical school will

receive training materials along with other valuable fuelsystem diagnostic and repair tool information. In addition, students in the program will receive an

official PUMP•ED performance pack that includes educational materials, tools and more.For more information, visit: www.airtexproducts.com.

What’s happening

Enter the 2015 Krazy PaintPinstripers Design Contest!Krazy Paint Pinstripers will create a

design for the 49th annual SummitRacing Equipment I-X Piston PoweredAuto-Rama Presented by RAD AIRComplete Car Care and Tire Centers. The 2015 Krazy Paint Pinstripers

Official Design Contest ends onOctober 20, 2014. Official Rules andmore information is available at theevent’s website at:www.ixpistonpoweredautorama.com

under the Show Features tab.Pinstripers will be able to submit

any number of original entries onactual panels or digitally. The three winners will be notified on

October 31, 2014. The 1st place prizeis $500, 2nd place prize is $250, 3rdplace prize is $100.

Fox Valley Technical College reported the expan-sion project at its J. J. Keller Transportation Center inAppleton, WI, was recently completed. For more onthe school’s automotive and transportation program,visit: www.fvtc.edu/public.

RED KAP Joins School of the YearSponsorshipRed Kap, a manufacturer and distributor of

comfortable, durablework-related clothing andouterwear, has joined WIXFilters in sponsoring twoBabcox Media automotiveexcellence awards in 2014.“Red Kap manufactures

work apparel specific tothe automotive market, making our brand the per-fect addition to award programs recognizingworkplace excellence in the aftermarket industry,”said Leslie Hunt, marketing manager for Red Kap.“We are proud to align the Red Kap brand withWIX Filters in support of those who represent thebest in the industry.”As part of the sponsorship, Red Kap will provide

uniforms and merchandise to winners of the following awards:School of the Year – Open to all high schools or

post-secondary schools that have a subscription toTomorrow’s Tech magazine. Red Kap will provide hats or shirts to the four

finalists, as well as a uniform for every student ofthe winning school. For more information, visit

www.ttschooloftheyear.com.


AutoCare Career Hub knows how difficultand stressful job searches can be.Sometimes, it feels like you’re just unableto burst through and make the bestimpression in the middle of a stressful job

search, especially when you have so many other thingson the front of your mind. Don’t let these things affectyou, though! Take our advice and

eliminate little mis-takes that have a hugeimpact on finding yournext auto technicianjob. Everything fromineligible resumes tochatty interviews canruin your chances at ajob. Improve yourchances with thesehandy tips.

1. MediocreReferences Aren’tGood References:�Surely everyoneknows to stay away from bad references, but what aboutthe ones that are not good, but not bad? Those types ofreferences can look even worse to a recruiter. Don’t askfor a reference if you know that they won’t go the extramile for you.

2. Negative Talk About Former Employers: Althoughthe phrase, “if you don’t have something nice to say,don’t say it at all,” still holds true, sometimes it speaksvolumes to say something positive about a bad formersituation. Yes, you were laid off, but what was the positivethat came out of that situation? No job recruiter wants tofocus on the negatives. Neither should you.

3. A Bad Resume:�A lot of people think that the morestuff they cram on their resume, the better it will be.That’s not going to help, especially if the job recruitercan’t read it. Never use a hard to read or small font andalways check your spelling and grammar.

4. Saying Too Much In An Interview:�The interview is aconversation between two parties, not a speech given byyou. Keep your talking to concise points, be inquisitive,listen to what the recruiter says and end your responseswith a good question to further the conversation.

5. Being Too Hard On Yourself:�Once again, negativitycan seriously damper the job process. Put a positive spinon everything, and if you really don’t think that you’regood enough for the job, tell the recruiter that you nolonger want to be considered. You can be assured that ifyou’re hard on yourself, the recruiter will be too.

6. Focusing On HowLong and Difficult YourJob Search Has Been:Even if you’ve been on thehunt for years, you can stillfind a way to talk positivelyabout the experience.Focus on the great con-tacts you’ve made duringthat time, the training andknowledge you’ve beenable to fine-tune, and thetrends that you were ableto keep up with.

7. Being Too Honest:�It’salways tricky to answerthe “tell me about your

greatest weakness” question. Focus on how you correctedthe weakness and overcame a challenge instead ofdivulging too much about what’s wrong with you.

8. Don’t Force Things:�The job process takes a longtime. Things can drag on for a while, especially whenthere are many people involved with the hire. Don’tpester a company until they become annoyed with you.Instead, close each meeting with a hiring manager by asking what you should expect next in terms of the hiringtimeline.

9. Don’t Talk Salary Too Soon:�There’s a time to talksalary, and a time to prove that you’re worth the salary. Ifyou focus early on in the interview process on youraccomplishments and worth to the company instead ofwhat you want to make, it’ll be easier later on to have adiscussion about how much you expect to make.

10. Applying to Jobs Blindly:�You need to focus on jobopenings that you have connections to, not jobs postedin a classified or general job site. Use niche websites, likeAutoCareCareerHub, that already have a strong networkfor you to tap into. Then, use your already existing network to find more job leads. �

Career Corner

10 TIPS TO IMPROVE JOB SEARCHES

Photo Courtesy of 3A Automotive, Phoenix, AZ

By Libby Melhushttp://autocarecareerhub.com

Each month, Tomorrow’s Tech takes a look at some of the automotive-related student competitions taking place in this country, as well asthe world. Throughout the year in “Finish Line,” we will highlight not only the programs and information on how schools can enter, butwe’ll also profile some of the top competitors in those programs.Because there are good students and instructors in these events, we feel it’s time to give these competitors the recognition they deserve.

edited by Tomorrow’s Tech staff


Wisconsin Students Take Top Honors at National Ford/AAA Auto Skills Competition

Justin Bublitz and Colt Morris fromGrafton High School in Grafton, WI,have claimed the crown of America’stop student auto technicians at theannual Ford/AAA Student Auto Skills

national competition.The Wisconsin students, who registered thetop score under the tutelage of instructor CarlHader, outlast 98 others to claim their prize —and honors.Students from across the country gathered inDearborn June 10, to match wits and workman-ship in a race against the clock – and one anoth-er – for the right to claim a NationalChampionship and be named the top youngautomotive minds in America at the 65th annualFord/AAA Student Auto Skills National Finals atFord World Headquarters.The competition, held on the grounds of Fordheadquarters, began at 8:30 a.m., and when thedust settled nearly 90 minutes later, Bublitz andMorris drove their 2014 Ford Fusion into the

Final Judging staging area with a completed“service repair” order.

Taking the Field�With more than $10 million dollars inscholarship prizes in the balance, statewinners gathered in Dearborn to solve“real world” automotive challenges – bothdigital and mechanical – in a timed competition.A quick mind and steady hands wererequired as top auto students worked withwrenches and computers alike. With automotive sales up across theboard, and new and innovative technologiesbecoming a bigger part of the manufacturing

Photos courtesy Ford/AAA Student Auto Skills


process, the Ford/AAA StudentAuto Skills competition is shapingthe next generation of auto techni-cians who will work on these vehicles.Beginning with a shotgun start,the student competitors (all pairedin two-person teams) raced totheir vehicles to review a workorder that challenged them todiagnose and repair a number ofpurposefully placed “bugs” ranging from digital to mechanicaland electrical. Once the repairs were complet-ed, it was a race to shut the hood,fire up the engine and steer thevehicle across the finish line –where a scrutinizing judging teamawaited.To earn the National Title,Bublitz and Morris earned a “perfect car” score by flawlesslyrepairing all the “bugs” withoutany demerits. Students are gradedon quality repair workmanship andsafety. Combined with the resultsof a written examination taken onJune 9, their score allowed themto hoist the trophy as nationalchampions.

‘Extra Credit’In addition to scholarships, theNational Champion Wisconsinteam enjoyed an immersive, week-long job shadow experience with

2011 Daytona 500 winner TrevorBayne and his Wood BrothersRacing team, and the No. 21Motorcraft/Quick Lane Ford Fusioncar at the Coke Zero 400 inDaytona Beach, FL, – the famoussite of Bayne’s spectacular win atage 20.

“For today’s automotive technicians, being able to diagnoseand repair a computer-related mal-function is just as critical as fixingmechanical failures,” said MarshallL. Doney, AAA Chief OperatingOfficer.“As a generation that has grownup with digital technology, this

year’s students are uniquely qualified to lead the auto industryforward and you saw their brillianceon display today in a high-octaneatmosphere matching the nation’sbest talent from coast-to-coast.”“The automotive technicians oftomorrow must be well-educatedand highly-skilled to meet the current and future technologicaladvances in automotive technolo-gy,” said Steve DeAngelis, Ford’sManager of Technical SupportOperations.“The people at Ford are committed to training and retainingthe best technicians in the industry,which is why we are so proud of ourcontinued involvement in theFord/AAA Student Auto Skills com-petition, which invests in our highly-skilled technicians of tomorrow.”

For additional information on thecompetition, visit:autoskills.aaa.com.

Do you have an outstandingstudent or a group of students that needs to berecognized for an automotive-related academicachievement? E-mail us at [email protected].

Ford/AAA 2014 Top 10 Finishers

1. Wisconsin2. Oklahoma3. Maine4. Oregon5. Hawaii

6. Massachusetts7. Rhode Island

8. Iowa9. Kansas 10. Nevada


The electric vehicle’s (EV) popularity among con-sumers is rising due to its zero emissions,increased efficiency and lower operating costs.While some will choose to purchase a new EV,there has been a growing group of enthusiasts

who would rather convert or have someone else switchtheir petroleum-burning vehicles into electric drive. So why convert a vehicle? It all boils down to cost. Thisarticle will cover a conversion performed on a 2001 ChryslerPT Cruiser (EV Cruiser) with a total conversion cost of about$12,000. This might seem like a high price to pay, but with adaily operating cost of 50 cents per day, it’s easy to see howthe cost can be recoverable. One main item that preventsconsumers from moving toward an EV is the fear of anexpensive battery. Although the batteries in the EV Cruiserare rated to last about eight to 10 years, with the way the EVCruiser has been driven, the battery cost of $5,500 shouldbe recovered after five years of use. It took about one yearto finish our project, which included six months of waiting forthe batteries to arrive. The choice between buying and converting is based onfinances, fabrication skills, desired range and comfort ameni-ties. Increasing the desired range and comfort level of thevehicle will drastically increase an EV purchase or projectcost. For example, the $87,400 Tesla Model S rated to go275 EPA-certified miles on a single charge comes with all thecreature comforts of a luxury vehicle — including a 17”touchscreen infotainment system. On the other side of thespectrum is the Mitsubishi i-MiEV. For $29,000 this vehiclewill drive for 62 miles on a single charge, but the comfortlevel is similar to a base model sub-compact.

Conversion Phases: Design Converting a vehicle into an EV can be categorized intothree phases: design, teardown and assembly, and testing.Designing the vehicle starts with specifying the type of systemdesired, amount of range and the types of accessoriesdesired. Thoroughness and specificity is key when designing.It is the most challenging and time-consuming phase, buthaving a robust plan of action will prevent any waste of timeor finances. Fortunately, EV conversions are not new and there are

numerous credible resources on the web that have chronicledEV conversions on various types of vehicles. The EV community is a very tightknit and helpful group of peoplewho are willing to share information and assist with any typeof EV project. Having this type of resource and supportallows for a thorough design and a successful conversion.The EV Cruiser was designed with three goals: to attain 35

miles of range, a top speed of 70 mph, and to cause mini-mal alterations to the vehicle. During the design phase, thefirst step was to choose between an alternating current (AC)or a direct current (DC) powertrain system. The pricebetween the two systems can vary as much $3,000 to$6,000 depending on the type of motor and controller. Justlike most purchases, all of the major components on an EVproject will increase in price as efficiency increases. AC conversion kits cost more, but they are also more efficientand can be programed to enable regenerative braking. Onthe contrary, DC conversion kits cost less, but are less efficient

Real World By Omar Trinidad, Assistant Professor, Automotive Technology,and Ralph Tate, Associate Professor,Southern Illinois University

CONVERTING THE MASSES

Figure 1

and are unable to utilizeregenerative braking. Tokeep costs low, the EVCruiser was designed with aDC Logisystems WarP-Corecontroller rated at 750 ampsand a 9” Netgain WarPseries wound DC motor rated at 34 horsepower at 144volts, and 100 lbs.-ft. at 500 amps (see Figure 1). The motoris equipped with carbon brushes, which are designed towithstand about 50,000 miles of use. Part of the design phase was specifying battery types andmounting locations. The two main choices of batteries wereconventional 12-volt lead acid batteries and lithium-basedbatteries. Lead acid batteries are more affordable, but aresignificantly heavier compared to the more powerful lithium-based batteries. In order to increase range by decreasingweight, the EV Cruiser utilizes 38 prismatic-type cells of lithi-um iron phosphate (LiFePO4). Each cell is wired in series toprovide 120 nominal volts (see Figure 2). To charge theLiFePO4 batteries, an Elcon PFC1500 charger rated at 1.5kWwas mounted in the engine bay (Figure 1). It is designed tocharge using a 1.5kW Level-1 charger directly from a regular120V AC outlet, or a 3kW Level-2 charger similar to a 240VAC dryer outlet (see Figure 3). Part of the lithium batteries’ cost comes from the BMS(battery management system), which protects it from failingdue to heat and over-charging. The BMS in Figure 4 illustrates how each cell is monitored and managed to maintain a certain temperature and voltage. In addition tothe BMS, a relayed system with a shunt resistor must be used

to precharge the system before fully connecting both sidesof the battery to the controller. Similar to the three systemmain relays on the Toyota Prius and other hybrids, the BMSprotects the controller from the high-voltage shock of thebatteries, though unlike the Toyota Prius, the EV Cruiser isdesigned with two contactors wired in series (see Figure 5).Based on the design of the vehicle, the batteries are eitherstored in place of the gas tank, inside the newly gutted andspacious engine compartment, or beneath the passengerseats (Figure 2). On trucks however, the battery boxes canbe designed to fit beneath the truck bed to allow utilization.

Some opt to place the battery box where the sparetire was stored. No matter where the batteries will bestored, it’s important to keep in mind that the EV uti-lizes a high-voltage DC system and that the batteriescan produce a flammable gas when charging. Thus,safety must always trump range or aesthetics. One of the main goals of this project was to keepalteration and cost of the vehicle to a minimum. Theamount of accessories was kept to a minimum by

removing the power steering system, and the heating andair conditioning functions (HVAC). Similar to most projects,funding will be the main variable that will increase ordecrease the inverse correlation between range and com-fort. The main drawback to a minimalistic vehicle is a less“normal” driving experience.

It is possible, depending on the design of the electricmotor and drivetrain, to utilize the other side of the motorshaft to drive an accessory pulley. This pulley can providetorque to the power steering pump, AC compressor andalternator. The main drawback to this system is the amountof energy it will drain from the battery to power the accessories. Some vehicles do not allow for this system, butan electric power steering pump and AC compressor canprovide the pressure to keep the original systems functional.


Figure 2

Figure 4

Figure 5

Figure 3

One of the main disadvantages ofan EV, regardless of whether the vehi-cle is a conversion or not, is theamount of energy the HVAC systemdraws from the batteries. The amountis second only to the motor and con-troller. For example, Mitsubishi’s i-MiEV is designed with a 47kW motorand an HVAC system with a combinedmax power rating of 9.5kW, whichmakes it one of the most conserva-tively produced EVs. There are twoheating system types available for EVconversions: the first utilizes a ceramicheater that replaces the heater core,the second is a heating system thatcan be plumbed to the heater core toutilize the existing plumbing system. Even though the utilization of theHVAC system will be based on loca-tion and desired comfort, it is stillessential to have a 12-volt systemand a vacuum pump for the brakebooster. The 12-volt system can bemaintained by a DC-to-DC converteror an alternator. The vacuum pumpsystem must be designed with apressure sensor to stop the pump atabout 21 inHg. These pumps can bepurchased from an automotive manu-facturer that utilizes vacuum pumpson some of their vehicles or from anEV conversion vendor. Although the transmission is not

considered an accessory, it is anothercomponent in which a decisionbetween range and comfort has to betaken. Based on the desired topspeed and drivetrain configuration,torque from the motor can be directly

applied to the rear differential ortransmission for a rear-wheel-drivevehicle, or through a transaxle on afront-wheel-drive system. Utilizing anautomatic transmission will requirehaving a programmable controller toprogram the shift points, a fabricatedcoupler to transfer torque to the inputshaft of the transmission, and an auxil-iary transmission fluid pump to sustainfluid pressures while the motor is notspinning at idle. The EV Cruiser utilizes the originalmanual transmission without a clutchto minimize alterations to the vehicle,keep costs low and to increase range.For optimum speed, the transmissionis initially shifted into second gearthen to third for more speed. Shiftingwithout the clutch may take sometime to get used to, but when timedproperly, the synchronizers allow forsmooth upshifts.

Teardown & Assembly Once the desired system and rangeare specified, the teardown andassembly phase starts. This phasebegins by removing the internalcombustion engine (ICE), emissions,exhaust, fuel and cooling systemcomponents. Furthermore, based onthe desired accessories, other com-ponents such as the HVAC compo-nents would need to be removed toreduce weight. One of the main tasks for this phaseis fabricating the battery boxes,adapter plate, motor mounts and coupler. The battery boxes on the EV

Figure 6

Continues on page 52

If ever there was a service opportunity ripe for thetaking, Chrysler’s 3.5L SOHC V6 engine (and its2.7L, 3.2L and 4.0L cousins) is it. This engine wasintroduced back in 1993 as an “upgrade” from theearlier 3.3L pushrod V6 engine. Some would ques-

tion whether the move was a step forward or backwardbecause the 3.5L V6 (and its variants) has a poor reputation for reliability. Lubrication issues, oil sludging,coolant leaks, overheating and low-mileage engine failureshave plagued this engine family from the get-go. Some blame the design of the engine itself for all

the ills it has suffered, while others blame consumersfor not maintaining their engines properly. Butregardless of who’s at fault, these engines do repre-sent a significant service opportunity.

Engine DetailsThe new 3.5L engine used essentially the same cast ironblock and crankshaft as the 3.3L (same 81 mm stroke),but the bore size was increased from 93 to 96 mm andthe compression ratio was bumped up to 10.4:1.


The 3.5L engine is an even-firing power plant with

aluminum cylinder heads, a single camshaft in

each cylinder head and four valves per cylinder. It

has a sequential fuel injection system with distrib-

utorless ignition. The engine is rated from 214 to

220 horsepower depending on the model year,

and delivers good torque from 2,000 to 5,600 rpm.

Engine SeriesAdapted from Larry Carley’s article in

KEEPING THE 3.5 ALIVEService Notes for Chrysler’s V6 Engine Built from 1993-2010

Chrysler designed new headsand manifolds to accommodatethe overhead cams, and a sexydual-throttle cross ram intake sys-tem with a manifold tuning valve. The front of the block was modi-

fied to accommodate a front-mount oil pump and a timing beltdrive for the overhead cams. Thewater pump was built into thefront cover so it could be drivenby the timing belt. The pistons are cast aluminum

with full floating wrist pins, ductileiron compression rings, and arerelived so the engine will free-wheel without valve interference ifthe timing belt breaks.

Under the HoodsThe 3.5L V6 was used in 1993-’97Chrysler LH cars (Dodge Intrepid,Chrysler New Yorker and LHS,Eagle Vision) and the ’97Plymouth Prowler.In 1998, the 3.5L was reworked

and given an aluminum block andadditional tweaks to increase thepower to 253 to 255 hp, dependingon the application. Unfortunately,Chrysler failed to upgrade somethings that needed to be upgraded,like the undersized oil galley pas-sages in the block, the troublesomecoolant pipe that runs under theintake manifold, the undersized PCVsystem that doesn’t pull enough airthrough the crankcase and the over-all reliability of the engine itself.The 1998 to 2010 all-aluminum

versions of the 3.5L SOHC V6were used in a wide range ofChrysler models including the 300and 300M, Avenger, Challenger,Charger, Concorde, Intrepid,Pacifica, Prowler and Sebring.The last 3.5L V6s were produced

in 2010. For model year 2011, theengine was replaced with a totallynew 3.6L DOHC Pentastar V6.

Coolant LeaksAny engine can develop coolantleaks after years of service, andthe 3.5L V6 is no exception. Theseengines have a small metal heatertube that runs from the front ofthe engine under the intake mani-fold. There’s an O-ring seal at thefront of the engine that tends tofail and leak after so many years ofservice. The metal tube can alsorust from the inside out and leakcoolant. Replacing this tube is alabor-intensive and time-consum-ing repair job, as it requiresremoving the upper intake mani-fold and fuel injector rail.The replacement O-ring is P/N

06505692AA, and the metal tubeis P/N 04792185AC. Replace bothat the same time to prevent fur-ther trouble down the road.The cooling system on the 3.5L

uses a water pump with a moldedplastic impeller. The design ismore efficient than a typicalstamped metal impeller and pro-duces less cavitation, but the softplastic impeller can be eroded andworn down by rust and sedimentin the coolant. If this happens, thepump won’t circulate as muchcoolant, causing the engine to runhot and overheat.If an engine is running hot and

there are no obvious externalcoolant leaks, and the radiatorcooling fans are cycling on and off,and the radiator isn’t clogged orobstructed, pressure test the cool-ing system to check for an internalcoolant leak. Leaky head gasketsare also a common problem onthese engines.

If the cooling system holds pressure, and the coolingfans are functioning normally, but the engine is runninghotter than normal, it’s probably a worn water pump. If you do change the water pump, change the ther-

mostat too. One other possibility would be a restrictedcatalytic converter that’s creating backpressure andcausing heat to remain in the engine.Regular coolant maintenance is absolutely essential

on these engines, so if the coolant has not beenchanged in five years, it may be time to drain, flush andrefill the cooling system. Using a coolant exchangemachine will make it easier to keep air out of the system.For 2001 and newer vehicles, Chrysler recommends a

long-life HOAT (Hybrid Organic AcidTechnology) or GO-5 type of antifreezethat meets its MS9769 requirements. HOAT coolants contain a combination of

inorganic acid and organic additives foradded protection against aluminum corrosion, which is important with the all-aluminum 3.5L engines. The same coolantcan be used in the older 1993-2000 applications instead of a conventionalgreen formula coolant.If you’re replacing a water pump, be

sure to inspect the upper and lower radia-tor hoses, and heater hoses. Replace any hose that is not in perfect

condition. If the hoses are more than 10years old, replace all of them.

On 2006-’08 Dodge Charger and Magnum andChrysler 300 vehicles, Chrysler issued a recall(L08110617-010) regarding a fan separation problem.It only applies to cars equipped with the severe-dutycooling package. The free fix involves replacing bothfans with new ones (P/N CBHZL080AA) that hopefullywon’t come apart and damage the radiator.

Oil Sludging ProblemOne of the most common problems with theseengines is that the oil tends to sludge and breakdown — especially if the oil is not changed every3,000 miles. These engines run hot, and with a PCV


system that barely flows enough air to pull moistureout of the crankcase, it doesn’t take long to create anoil sludging problem.As sludge and varnish build up inside the engine, it

can restrict the small oil passages that deliver oil tothe crankshaft bearings, increasing the risk of oil star-vation and bearing failure. Many of these engineshave failed at relatively low mileages (less than 80,000miles) because of spun bearings and/or broken con-necting rods. If you have a customer who drives a Chrysler prod-

uct with a 3.5L V6 (or a 2.7L, 3.3L or 4.0L), you needto stress the importance of frequent oil changes(every 3,000 miles, not the 7,500-mile intervals recom-mended by Chrysler). If you find evidence of maintenance neglect such as

foaming or sludge on the underside of the oil fillercap, a plugged PCV system or oil that looks like tarwhen it drains out of the crankcase, recommend acrankcase flush to remove as much of the accumulat-ed sludge and varnish as possible when the oil ischanged. Also, inspect and clean the PCV valve when the oil is

changed, and replace the PCV valve every 30,000 milesto keep the PCV system working at peak efficiency.

Note: Chrysler technical service bulletin (09-01-96)describes a hydraulic lash adjuster noise problem withthis engine. A heavy clicking or ticking noise comingfrom the top of the engine that changes with rpmmay occur due to oil aeration if the crankcase is over-filled with oil. If the noise persists after correcting theoil level, it may indicate valvetrain damage.

Don’t Forget the Timing BeltChrysler probably should have used a timing chain inthis engine, but instead opted for a less expensivetiming belt. The factory recommended replacementinterval for the belt is 100,000 miles.The early 1993-’97 3.5L engines are non-interference

engines, so if the timing belt snaps or jumps time, theengine won’t bend any valves. The all-aluminum 1998-2010 engines, however, are interference engines. If thetiming belt is not replaced at the recommendedmileage, the risk of belt failure increases with everymile that’s driven. If the belt breaks, the vehicle ownerwill be looking at a very expensive repair. On oldercars, the cost of the engine repairs will be more thanthe car is worth.Replacing a timing belt on a 3.5L V6 is typically a

two- to three-hour job, so the cost of preventivemaintenance is relatively cheap compared to what abroken timing belt could cost the vehicle owner.The life of the water pump is about the same as the

timing belt, so if you’re replacing one, you shouldreplace both at the same time.

Other Preventive MaintenanceThe newer 3.5L V6s came factory-equipped with long-life platinum resistor spark plugs with a recommendedreplacement interval of 100,000 miles. The first generation 1993-’97 engines have conventional60,000-mile plugs. Replace them with same or betterand gap to 0.048” to 0.053” on the ’98-and-newerengines, and 0.035” on the ’93 to ’97 engines.The second generation 1998-and-newer 3.5L

engines have a coil-on-plug ignition system, so youobviously have to remove the coils before you change


The oil pan on the 3.5L is made of Antiphon steel,

which consists of a layer of rubber sandwiched

between two layers of steel. This deadens sound

transmission and helps reduce noise. Fill capacity

is 5 quarts when changing the oil.

The engine is even-firing, with a firing order of

1-2-3-4-5-6. Cylinder #1 is at the right front,

with #1, #3 and #5 on the right bank and #2, #4

and #6 on the left bank.

*Excludes sales tax. See website for details.

DAVID TYLER

/// Hot Shot Delivery. Just one more extra mile we go for guys like David.

the plugs. Be sure to inspect the long tube

on each coil that fits down overthe spark plugs for cracks or car-bon tracking. Replace as neededto prevent misfires.

Caution: Chrysler TSB 18-024-01 warns against cranking theengine with any of the coilsremoved. If any of the coil circuitsshorts to ground in the enginebay, you can damage the coil driv-er circuits in the PCM!Also, if you notice oil residue on

any of the spark plugs, the sparkplug tubes in the valve cover andthe valve cover gasket might beleaking. Replace them as needed.On the first-generation engines

with a distributorless ignition sys-tem, be sure to inspect the sparkplug wires when changing theplugs. The original suppressionwires on a high-mileage enginewill likely need to be replaced.

Be careful when changing thespark plug wires. The wires rununder the fuel rail on the left sideof the engine. There should beenough clearance to run the wiresunder the fuel rail without havingto remove it. Don’t attempt tobend or force the fuel rail upwardfor added clearance as doing somay damage the rail. Also, changeone wire at a time so you don’tmix up the firing order.The older 3.5L V6 engines have

two drive belts, a poly V-belt (flatbelt) for the alternator and powersteering pump, and a conventionalV-belt for the A/C compressor. Sounlike the newer 3.5L engines thatuse a serpentine belt with an auto-matic tensioner, tension on bothbelts needs to be checked andadjusted periodically. Each belt hasits own separate tensioner pulley.Chrysler recommends adjusting thebelts on the older engines every

15,000 miles. Use a belt gauge tocheck and adjust the tension. For the flat poly V-belt, set the

tension to 190 lbs. (new) or 160lbs. (used). For the A/C compres-sor V-belt, set the tension to 160lbs. (new) or 120 lbs. (used).

Miscellaneous FixesIf you encounter a 2008 Chrysler300, Magnum or Charger with aMIL light on and a DTC P050D(cold start rough idle set), thePCM may need to be reflashedwith updated programming toeliminate the false code. Refer toChrysler TSB 18-031-08 fordetails.On some 2008 and 2009

Chrysler 300, Magnum andCharger models with the 3.5L V6,a strange whistling noise may beheard in the engine compartment

while the engine is running. Itcould be a vacuum leak, but itcould also be a noisy purge con-trol solenoid. Chrysler TSB 18-036-08 says the fix for this is to repro-gram the PCM with updated soft-ware that corrects the condition.On 2009-’10 Dodge Challengers

and 2008-’10 Chrysler 300, Magnumand Charger cars, the MIL may comeon because of a false DTC P0339code (crankshaft position sensorintermittent set). The fix is not toreplace the crank sensor, but toreprogram the PCM with a softwareupdate (TSB 18-005-11). If the code persists after the

software update, it may be necessary to shim the crank sensoror replace the crankshaft flexplate. �


Fuel pump replacement comebacks canbe costly and can hurt your reputation.One of the leading causes of failure isthe tank. If a vehicle gets 20 miles to thegallon, then more than 5,000 gallons of

gas (from many stations) will go through the tankin 100,000 miles. And during this time, sediment,rust and debris from the pump can find its wayinto the tank.

Capturing ContaminatesRemoving all contaminates is critical. If possible,have the tank steam-cleaned at a radiator shop

that performs these services. They can reconditiona tank and check for leaks that you may not beable to spot. Your goal in cleaning the tank is torestore the environment inside the tank to thesame state it was in when they put fuel inbefore it drove off the assembly line.If you think the new sock or strainer on the

full pump will catch all of the bad stuff, you arewrong. The typical sock or strainer is designedto catch contaminates that are between 50-100microns in diameter. Forty microns is the size ofa human hair. A typical inline fuel filter cancatch particles as small as 10 microns. The sock also has a limited capacity due to its

Service Advisor

A CLEAN FUEL TANK

Adapted from Andrew Markel’s article in

Improves A FuelPump's Diet

small surface area.Always install a new filter. Sounds simple, but it is

often forgotten. The old filter can restrict flow andmake the new pump work harder. This makes for ahotter running pump that fails sooner.

When Fuel Cab Become a ContaminateAlthough cases involving contaminated gasoline arerelatively rare nowadays, they still occur. In manycases, the technician has replaced the fuel pump ormass air flow (MAF) sensor to address a P0171/P0174“lean-condition” DTC with no result. In all likelihood, the technician didn’t consider thepossibility that the vehicle’s fuel might be contaminat-ed with E85 gasoline, diesel fuel, stale gasoline, or, toa lesser degree, sugar and water. The fact is that thefirst three fuel contaminants tend to lean out theair/fuel mixtures, while sugar and water generallycause intermittent cranking, no-start and stalling com-plaints. In total, and depending upon the percentagepresent in the fuel tank, contaminated fuel can mimicthe symptoms produced by defective fuel pumps, fuelinjectors and fuel control components like MAF sen-sors.

E85 GasolineAlthough it’s hard to think of E85gasoline as a fuel contaminant,it’s important to remember thatE85 is designed for use only inflex-fuel vehicles. Because pureethanol requires approximately150% more volume to support stoi-chiometric combustion than does pure gasoline, someearly flex-fuel vehicles use an ethanol sensor in the fuelline to estimate the volume of ethanol in the fuel. Later flex-fuel vehicles simply use data inputs from

their air/fuel ratio sensors to adjust fuel injector pulsewidth to accommodate increased volumes of ethanol.Most flex-fuel vehicles can be identified by an exteriorflex-fuel emblem and, in many cases, a yellow gas cap. Many motorists inadvertently top off their fuel with

E85 because they are unaware that E85 gas pumpnozzles are generally equipped with yellow covers.Immediately afterward, they begin experiencing lean-fuel driveability symptoms such as hard starting andloss of power accompanied by a P0171 or P0174DTC, depending upon the application. At this point, let’s note that “ethanol” and

“methanol” are distinctly differentalcohol compounds. Methanol isused in racing applicationsbecause its high latent heat ofvaporization keeps the enginecool, and because it pro-duces slightly morehorsepowerthan

gasoline. But, even with

those advantages,methanol has a major ten-

dency to corrode metal surfacesand degrade fuel hoses, O-rings and

other soft fuel system components.

Additional Fuel System Diagnostics and ServiceBad grounds and connections can kill a new pump.Check the connector for any signs of thermal damagethat may indicate there was a voltage drop or a circuit


with high resistance. Do not assume the oldpump caused the thermal damage. Bad groundsand circuits will stay with the vehicle and dam-age the new pump. Filter the fuel before you put it back in the

tank. If a fuel pump went through a full melt-down, chances are the pieces from the old pumpare still in the removed fuel. Filter the fuelbefore it goes back in the tank. Many fuel cad-dies have built-in filters. Check the EVAP system before returning the

car to the customer. It takes at least one drivecycle for most vehicles to set an EVAP code. Aleak due to disturbing the lines may not set acode during the initial test drive. The code maycome on after the vehicle has been sitting for awhile or a certain temperature has beenreached. Check the system with a scan tool and/or

smoke machine before delivering the car to thecustomer. Some scan tools and vehicles can per-form a self-leak check. Fuel filler necks are espe-cially susceptible to leaks if the tank has beendropped. In the Rust Belt states, corrosion on the top of

the tanks and on the fuel lines is starting tobecome a big headache during fuel pumpreplacement. This is due to brines being used onroads to prevent icing. Brines stick to vehicles —even the tops of fuel tanks — long after thesnow storms have passed and even into summer.Then, every time it rains, the brines are reactivatedand start to corrode the tank.Also, check the straps and mounting hardware


of the tank. In 2010, Ford recalled 1.2 mil-lion trucks due to corrosion of the strapsthat held in the gas tank.

Note: It’s a good practice to inspect thefuel lines for corrosion before starting thejob. Nothing is worse than having to callthe customer because a line collapsed dueto corrosion during removal or installation.

Fuel Tank Cleaning Procedures1. Once the tank has been removed,

drain all fuel from the tank. Use only anapproved container or a fuel caddy to filter and store the fuel.2. Clean accumulated road debris or

rust from the top of the fuel tank, especiallyaround the module or hanger assembly toavoid contaminating the fuel tank.3. Remove the lock ring.4. Remove the module or hanger assembly.5. Clean and flush the tank with water before

installing the new module or hanger assembly.6. Swish the fuel tank around in a circular motion

to collect any debris remaining in the fuel tank.7. Slowly and carefully poor the fuel out of the

tank into the approved container or fuel caddy.8. Turn the fuel tank over, then tap the bottom to

remove any debris.9. Clean the inside of fuel tank with dish soap and

water. Modern fuel tanks are difficult to clean becauseof their internal baffling. If a tank can be cleaned, it’s important to use high-

pressure soap and water to remove the dirt. The tank

should then be thoroughly dried by circulating airthrough the tank or by simply placing it in the summer sun. In many cases, a fuel tank replacement isthe most cost-effective and safe alternative.10. If possible, take a lint-free shop towel and

wipe the inside of the fuel tank until it is clean.11. Dry out the fuel tank completely with

compressed air.12. Inspect the fuel tank carefully. If the tank is

rusted inside or shows signs of physical damage, itmust be repaired or replaced.13. After the tank has been dried with compressed

air, let it sit for 30 minutes. �



Thanks toadvancedtechnology,modern vehicles

operate with fewernoise, vibration andharshness (NVH) complaints than everbefore. Consequently, when

a noise, vibration orharshness issue arises,it’s most likely to becaused by worn drive-train components likeuniversal joints, constant velocity (CV)joints or wheel bearinghub assemblies. In anycase, NVH complaintscan often be the mostchallenging to diagnosewhen a tech or service writer can’t duplicate theexact driving conditions under which they occur.If the noise can’t be duplicated and verified on

a test drive, it’s doubly important for the servicewriter to determine during the customer interview when and how the particular NVH complaint occurs. Remember also that some wheel bearing

noises are transmitted through different parts ofthe chassis. To reduce diagnostic errors, verifynoises by using chassis-mounted sound detectors or by thoroughly inspecting all components while the vehicle is on the lift.

Joint WorkIn modern automotive architecture, universaljoints are most commonly found on the rearaxles of light trucks, SUVs and RWD passenger

cars. While some low-angle joints are made witha rubber-compounded material, most modernuniversal joints are made of a steel cross connecting four trunnions containing lubricatedneedle bearings.

See Photo 1.Eventually, the needle bearings wear grooves

into the case-hardened surfaces of the cross,which allows the propeller shaft to rotate slight-ly off-center. The rule-of-thumb spec for off-center rotation is generally 0.010” measured atthe end of the propeller shaft tube. In the mostcatastrophic cases, the lubricant in the trunnionbearings can be lost, which will cause the jointto eventually separate. Larger universal joints can be inspected for

extreme wear by twisting the propeller shaftback and forth.

UnderCover

Diagnosing NVH Complaints in Drivetrain Components

WHAT’S ALL THE HUBBUBON UNDERCAR NOISES?

Photo 1: Couplers are designed to operate at minimal angles ofdeflection and to dampen drivetrain noises.

Adapted from Gary Goms’ article in

Smaller joints can be tested byprying the trunnions back andforth with a large screwdriver.Preventive inspections can bemade by watching for rust forma-tions around the trunnion sealindicating that the trunnion haslost its lubrication. In anothercase, the driver might complainof a snapping or popping soundat low speed, which might indi-cate that the trunnions are seizingdue to lack of lubrication. Seizingcan be diagnosed only by removing the propeller shaft andchecking each universal joint forsmooth operation by hand.

See Photo 2.Because the trunnion bearings

are located at 90-degree intervals,a conventional universal joint actually accelerates and decelerates as it turns.To eliminate this uneven rotating

speed, universal joints are installedin pairs and phased along thesame plane on the propeller shaft.When the U-joints are correctlyphased, the propeller shaft speedsmooths out because one U-joint

accelerates as its companion jointdecelerates. Unfortunately, somesplined two-piece truck propellershafts can be incorrectly phasedduring reassembly. This conditioncan be difficult to detect sinceincorrect phasing often results in aharmonic vibration that resonatesunder different conditions ofspeed and load. For this reason, it’s always

important to index the propellershaft to its mating flanges and toits individual parts before replac-ing universal joints.Harmonic vibrations can also be

caused by universal joints operating at unequal angles ofdeflection at the propeller shaft.These angles should be measuredwith the vehicle at normal suspen-sion height and load. In someapplications, the angle at the rearaxle can be adjusted, either withshims or by a control arm eccen-tric, to allow the rear axle piniongear shaft to operate in the sameplane as the transmission or trans-fer case output shaft.

See Photo 3.

Photo 2: While a noise from a bad propeller shaft support bearingmight sound like a bad wheel bearing, it will resonate at approxi-mately three times wheel speed.

Although some U-joints are serviced as a unit withthe propeller shaft, most can be replaced. Using ahand-held universal joint press will prevent damage tothe propeller shaft, as will soaking the joint in penetrating oil before removal. If required, pack theneedle bearings with chassis grease and always lubricate the propeller shaft loops before assembly. Ifused, grease zerks should point toward the propellershaft and be aligned along the same plane. If the U-joint feels too stiff after it has been installed, align thetrunnions by tapping the propeller shaft loops with amedium-sized hammer.

Constant Velocity JointsCV joints have made life much easier for techsbecause, as the name implies, CV joints operate at amore constant speed than do conventional universaljoints. They do, however, tend to operate moresmoothly when the right and left axle shafts are oper-ating at equal angles of deflection. The most common CV joint failures are caused by a

loss of lubricant through a torn or perforated CVboot. The symptom of a leaking CV boot is a lubricant“spray” collecting on the chassis surfaces surroundingthe joint. When the lubricant is completely gone, thejoint will wear out and eventually separate. The most common symptom of worn CV joints is the

clicking noise that characteristically occurs when thevehicle is driven through a short right- or left-handturning radius under power. On rare occasion, a CVjoint will seize, which causes a wobbling sensation inthe steering wheel. A potential catastrophic failuremight be indicated when the transmission engage-ment between drive and reverse is accompanied by aclanking or knocking noise.

Several basic rules should cover CV half-shaft instal-lations. First, make it a habit to remove only one shaftat a time because there still are a few vehicles inwhich the differential carrier can drop to the bottomof the gear case when both axles are removed at thesame time. Next, avoid mixing the right- and left-hand shafts because some minor differences mightexist between their compression or extension lengths.Because using an impact wrench can damage the jointor adversely affect wheel bearing preload, always usea torque wrench to tighten the CV axle retaining nutto specification.

Hubs and BearingsBecause tapered-roller front wheel bearings requirefrequent lubrication and adjustments, permanentlypreloaded and lubricated bearing hub assemblieshave generally replaced them. Correct preloading isrequired in modern wheel bearing assembliesbecause the clearance between wheel speed sensorsand tone rings is critical. Preloaded bearings alsoreduce the rotating friction of the disc brake assem-blies by helping maintain a small, but significant, airgap between the brake rotor and pads.

When diagnosing any wheel bearing noise, it’simportant to remember that modern wheel bear-ings must:

1) Support the vertical load created by the vehicle’sweight,

2) Withstand the forward thrust of the drivingwheels, and

3) Resist lateral loading during cornering.Any noise coming from the wheel bearings will,

therefore, be most often duplicated under one ormore of these driving conditions.


Photo 3: Because this is an independent suspension system, the angle of deflection between the piniongear and propeller shaft is nearly zero.

When road-testing the vehicle toduplicate an NVH complaint,notice that wheel bearing and dri-vetrain noises are constant, where-as tire noises vary according to theroad surface.

See Photo 4.If a vacant parking lot is avail-

able, weave the vehicle back andforth at low speed to alternately

load and unload the wheel bear-ings. Notice also if the noise level

changes as the vehicle stops andaccelerates. After the wheel bearings have

warmed up after an extendeddrive, check each bearing hub’stemperature with an infrared heatgun. In most cases, the defective

wheel bearing will indicate a high-er operating temperature.

See Photo 5.When replacing bearing hub

assemblies fitted into aluminumcontrol arms, try heating the con-trol arm with an electric paintremoval gun. In most cases, the aluminum will

expand enough to expediteremoval of the hub assembly.Expedite installation by thoroughlycleaning and lubricating the hub’smounting surfaces. Replace all retaining bolts as

required, apply lubricant or thread-locking compound as directed andtorque each to the manufacturer’sspecification.


Question: How do you checkwheel bearing play?Answer: Raise the vehicle so

the wheel is off the ground,then grab tire at the 12 and 6o’clock positions and rock thetire back and forth. As a rule,you should not feel any playor looseness if the vehicle hassealed wheel bearing car-tridges or hubs with sealedwheel bearing assemblies. Onolder vehicles with servicea-ble wheel bearings, a littleplay is normal but a lot ofplay is not. Refer to the vehi-cle’s service specifications forthe maximum amount ofacceptable play.Wheel bearing play can be

measured with a dial indicatorby placing the dial indicatoragainst the hub and rockingthe wheel in and out by hand.As a rule, you should see nomore than .005 inches of playin the bearings if the bearingsare good.You can also rotate the tire

by hand while measuringplay, but be careful not toconfuse rim or hub runout

Photo 4: Since this wheel bearing had plenty oflubricant, it’s safe to assume that the failure wascaused by a metallurgical problem.

Photo 5: Worn wheel bearings can cause clear-ance problems at the ABS sensor and store ABStrouble codes.

with looseness in the bearings. As a rule, hubrunout should be .0015 inches or less, and nomore than .002 to .003 inches of runout at thelip of the rim. If runout exceeds this amount,try reindexing the wheel on the hub, orremove the wheel and measure runout on therotor or hub itself.If there is still too much runout, cutting the

rotor with an on-car lathe can eliminate orreduce runout at the rotor.

You’ve seen them on therace track. You’ve seenthem on the street.You’ve seen them inspeed shops, in maga-

zine ads, online and probably oneBay, too. The product we’re talk-ing about is slotted and/or cross-drilled high performance brakerotors. They look great, no doubtabout it.It could be a “bling” thing with

many buyers, but it can also be aworthwhile performance upgrade.It all depends on the application,how the vehicle is driven andwhether the customer wants a setof performance rotors for show orfor go.

Size MattersOne way to increase the coolingcapacity of the brakes is to installlarger rotors. The bigger therotors, the more heat they canhandle. Unfortunately, it isn’t easy to

change the size of the rotors onmany vehicles. Bigger rotorsmean repositioning the calipersand/or going with large calipers,too. There are aftermarket conversion kits for some vehicles,but not for all.

Cashing in on SlotsSome serious racers today havegotten away from cross-drilledrotors and now run slotted rotorsor ones that use both slots andholes. Slotted rotors typicallyhave four to eight evenly spacedshallow grooves milled into bothsurfaces of the rotor. The slotsprovide the same pad ventingbenefits as holes, but with lessrisk of cracking because the slotsusually don’t extend all the waythrough the rotor (though somedo). The slots are usually angledand curved so they sweep underthe entire surface of the pads.This provides much better vent-ing than a series of holes.

Drilling to WinYears ago, racers started cross-drilling rotors with small holes toincrease cooling. Drilling 30 to40 evenly spaced holes throughthe rotors increased airflow andcooling for faster heat dissipation.The phenolic resins that are

used as binders to hold brakepads together give off vaporswhen they get extremely hot. Thegas can form a boundary layerbetween the pads and rotor that

The RotorReport:Drilled orSlotted?

reduces friction. The effect is similar to that of aplastic puck on an air hockey table. If the rotor is cross-drilled or slotted, the

holes or slots break up the boundary layer andprovide a path for the gas to escape. Now thepads can make full contact with the rotors formaximum braking effectiveness even when theyare sizzling hot.

Cracking UpCross-drilling rotors may seem like a great idea,but if done improperly, it can have serious con-sequences. Drilling a hole through the surface of a rotor

creates a stress point in the metal. If the edgesof the hole are not radius chamfered to dissipate the stresses, the hole may concentratestress to the point where cracks start to formand propagate outward from the hole.Cracks are something you don’t want in a

brake rotor because cracks can lead to catastrophic rotor failure! �


Leave it to the manufacturers to take asimple thing like heat and air conditioningand turn it into an electronic jungle ofwiring, sensors and computer compo-nents. HVAC units have come a long way

from when I started in the business. Not that I want to dwell on the past, but it

might be a good idea to make sure we under-stand the basics before diving into the problem oftoday’s systems. I always feel that if I understand a

system fully before doing any repair work, I’mmore likely to get it right the first time.

Diagnostic procedures vary from car to carand from year to year. I’m finding more andmore these days it’s a lot easier to diagnose theHVAC system with a scanner rather than with aprint-out and test light.

With the advent of the electronic door motorsand the crazy locations on some of these compo-nents, I would definitely try to use a scanner

Under the Hood

KEEPING YOUR COOL

Adapted from Scott Gonzo Weaver’s article in

WHEN DIAGNOSING A/C SYSTEMS

‘Overcharging’ A/C ServiceIn the world of public opinion, if youheard that technicians were ‘overcharg-ing their customers,’ you might inter-pret that as an issue pertaining to thecustomer’s repair bill.However, in the world of mobile airconditioning service, we’re referring tothe problem of some vehicle A/C sys-tems being (unknowingly) chargedwith too much refrigerant.A/C performance problems due to toomuch refrigerant in the system havebecome an issue in recentyears, as vehicle manufacturershave made the move to small-er A/C compressors in order toreduce weight and put lessloads on today’s smallerengines. When we look at the refriger-ant demands on older R-12 vehicles that operated underthe hoods with V8 and 6-cylinder engines, A/C systemsoperated on as much as 55 to 60 ounces! Today’s R134-asystems have 12 to 16 ounces of refrigerant to deal with.That’s not a lot of wiggle room when recharging a sys-tem.What the industry is finding these days is that if you

service and A/C system, butdon’t fully recover all of therefrigerant prior to the work,and then add a full charge tothe system, you may run the riskof overcharging. And, an addi-

tional 4 to 6 ounces of refrigerant in today’s smaller com-pressors will cause the A/C system to not operate effi-ciently, and lead the vehicle owner to return to yourshop complaining their “A/C system isn’t blowing coldair.”So pay extra attention when operating that A/C refrig-erant recovery equipment!


when possible. An interesting fact,some aftermarket scanners providea wealth of information onHVAC systems.

Before purchasing a -scanner, I would askwhether or not it coversHVAC units and whichyears, which models andhow thorough it is.

The more informationyou have before youget your hands dirty, thebetter.

One of the more com-mon repairs I’ve seen onboth domestics and importsis connections. The manufac-turers (in my opinion) havegone to the point of making theseconnections just barely survivable, but

not for the length of time that con-sumers are stretching their vehi-

cles’ useable years on the road.

The other item of concernis the control sensors, i.e.,high pressure sensor, lowpressure sensor, sun load,etc., for the most part, Iwouldn’t drag out thattest light and start stab-bing the wires. They maylook like a sensor, theymay have wires like sen-

sors, but there’s a goodpossibility that it’s not a

positive or negative signal atthe sensor. In some cases, the sensor

maybe reading a digital-type signal(waveform voltage) that would be easier

to read on a scanner screeninstead of that 12V test light.These values are then sent to thePCM to be interpreted and usedto determine the actual A/C clutchengagement or door positions.Here again, a scanner is the propertool of choice, not the test light.

Assuming we don’t have a com-ponent failure and that the entireproblem is a connection somewhere,let’s say at the blower switch, which

in some cases is also the “On”switch for the entire system.

If the plastic housing has beenmelted and the physical “metal”connector is skewed out of place,chances are that no matter howmuch manipulating you do to “re-fit” the metal tab back into place,it’s still going to end up back whereit started and your customer willbe back at your door with thesame problem. I would locate areplacement connector either fromthe dealer or the local parts store.(I’ve had next to no luck getting a

connector from the salvage yards.Most of the connectors that camefrom the salvage yard are just asbad as the one I already have inthe car. But, you might get lucky…)

The advantage of using a scannerto see certain sensor values anddoor positions also has one extraquality to the diagnostic process:Codes. Codes for the HVAC systemare valuable information for you asthe tech. However, a code is notthe answer, a code is a startingpoint or a direction for repair. Somany times I see vehicles come inwith new parts bolted in becausethe last shop that had it read acode and assumed that meant toreplace the part.

Beetle-JuiceA perfect example of this was a2002 VW Beetle that came in witha brand-new compressor and fan

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Photo Courtesy: German Audio Tech

controller on it. There was a codestored for poor compressor per-formance at idle, which was exactlywhat it was doing.

If the car was at idle and the A/Cwas off, rev the engine just slightlyand the compressor would turn onand work perfectly. Bring it back toan idle and the compressor wouldshut back off.

Checking into it a little further, Ifound the real culprit to be thecharging system. At an idle, thealternator couldn’t develop enoughoutput to maintain all the systems inthe car.

Since the computer wasn’t gettingenough ‘juice,’ the PCM would shutdown the A/C while trying to maintaina voltage level that was acceptable.

But this level never got to thepoint of causing the charge indicatorto come on during this wholeprocess. (Cars are getting too smartthese days.)

The best thing I can tell you aboutdiagnosing HVAC systems is to consider the year and make of thecar, find out whether or not a scanner can code, read values and/orgive you some information on thecondition of the components beforeyou start changing things. If thereisn’t access by way of a scanner, thenI would suggest a wiring diagramand a description page that willinform you of how each componentworks in that given system.

If you keep your cool, I’m sure youcan get it diagnosed and repairedbefore your customer gets too hot. �



Arunning compressiontest or dynamic com-pression test is animportant, but little-used and often over-

looked engine diagnostic tool. Whyis this test so significant? It can beused to pinpoint the cause of a mis-fire when all the usual tests returnnormal results. It’s also used by per-formance tuners to verify that eachcylinder is contributing equally tothe engine’s overall power output.When you perform a static com-

pression or cylinder leak-downtest, you’re checkingthe sealing capabilityof each cylinder. Avacuum test is a greatway to determine anengine’s overallbreathing capabilities,but does not provideresults for individualcylinders. The advan-tage of a running

compression test is that it givesyou an idea of the volumetric effi-ciency of each cylinder. In otherwords, how efficiently each cylin-der is pulling air in, retaining it forthe correct amount of time, thenreleasing it into the exhaust. If acylinder cannot perform thesefunctions properly, the result canbe a loss of volumetric efficiencyor a density misfire.

How to Perform the Test1. Create a chart similar to thisexample to record your test readings.

Tech Tips

FIRING ON ALL CYLINDERS?Running Compression Test is a GreatTool for Diagnosing Density Misfires


2. Begin with a normal ("static") compression test on awarm engine to eliminate obvious problems such as badlyworn rings, burnt or bent valves or holes in pistons. If youhave a diagnostic trouble code, you may know whichcylinder is misfiring, but it’s a good idea to test the com-pression of all the cylinders in that bank to get a goodcomparison. Record your static compression readings.

3. Install all of the spark plugs except the one forthe suspected cylinder.

WARNING: GROUND THAT PLUG WIRE TO PREVENT MODULE DAMAGE, OR WHEN EQUIPPEDWITH A COIL-ON-PLUG IGNITION, SIMPLY DISCONNECT THE COIL HARNESS PLUG.

4. Disconnect the injector for that cylinder on aport fuel injection system.

5. Install your compression tester in the suspectedcylinder. The test can be done with the Schrader valveremoved, but most techs recommend leaving the valvein the gauge and "burping" the gauge every 5-6"puffs."

6. Start the engine and take an “Idle” reading. Besure the idle speed is a consistent 1,200 rpm. Recordthe results.

7. Now, from 1,200 rpm, snap the throttle to 2,500rpm and release quickly. Reading should rise. Recordthe results.

NOTE: Don't use the gas pedal for this snap acceleration. The idea is to manually open then closethrottle as fast as possible, forcing the engine to take a"gulp" of air.

Sample Test ReadingsComparing measurements between cylinders is important. Running compression at idle should be 50-75 PSI (about half cranking compression). Snap throttlecompression should be about 80% of cranking compression. Let’s analyze the results from the following sample test readings.

In Example 1, cylinder #1 has a snap test reading

that is much lower than the other cylinders. If a snapreading is low (much less than 80% cranking compression),look for air intake problems such as severe carbondeposits on intake valves, worn cam lobe, worn valveguides and springs, rocker or push rod problems, or"shutter valve" miss-positioned in the runners of a variable runner intake system.

In Example 2, cylinder #4 has a higher than normalsnap test reading. If a Snap measurement is significantlyhigher (over 80% of cranking compression), it meansthe air is not leaving the cylinder efficiently. Look for problems on the exhaust side of that cylinder

such as worn cam lobe, bent push rod or collapsedlifter. If the snap readings are all high, look for exhaustrestrictions such as a clogged catalytic converter ormuffler.

In Example 3, cylinder #2 has a low Idle and snap testreading. These types of numbers indicate that the cylinder is not holding compression efficiently. Look forissues such as slightly bent or burned valves, excessivecarbon build-up on valves or seats, worn valve guidesand springs, scored cylinder wall, or a leaking head gasket. As you can see, information gathered from a running

compression test can be very helpful when diagnosingmisfires and tuning for total engine performance. It’s agreat test to add to your diagnostic arsenal.

Source: ALLDATA Community Diagnostic Team �

Solution at www.tomorrowstechnician.com

Tomorrow’s Technician August Crossword

CrossWord PuZZle ACROSS1. Cylinder sliders5. Components returned for remanufacture8. Unexpected engine stoppage9. Combustion ____, explosive area10. Inertia ____ seat belt11. Mirror image (4,4)13. Franchised vehicle vendor15. Two-prong fastener, ____ pin18. Ruined-fastener description19. CV-joint cover22. Engine-hood support (4,3)23. Cylinder-repair sleeve24. Showroom transactions25. Increases cylinder's diameter

DOWN1. Valve-train part, perhaps2. Cooling-system deposits3. Engine lubricants4. Six- or twelve-point tool5. Online discussion venue (4,4)6. Replacement-part description, perhaps7. Tapered fastener12. Carmaker-recommended replacements (1,1,1,5)14. Race-car downforce device16. Adjusts ignition timing, in a way17. Power-boosting exhaust manifold18. Tire-tread slits20. Pink-slip name21. Collector-car collectors' collective

Cruiser are fabricated from light-gauge steel, sealed witha silicon sealer, and then painted for protection from corro-sion. An adapter plate was fabricated to mate with thetransmission bell housing, hold the electric motor, and tomaintain the alignment and spacing between the two com-ponents (see Figure 6). Depending on the torque rating ofthe motor, special motor mounts or straps might be need-ed. Initially, the project was designed with the originalmotor mounts, but a high-performance solid rubber mountlater replaced this design.Since this project was designed to utilize the originally

equipped clutch system, a special coupler was designed toconnect the pressure plate and electric motor together.There are ways to have a clutchless system by fabricating acoupler to connect the electric motor output to the trans-mission input shaft. However, regardless of whether thevehicle will utilize a clutched or clutchless system, a damp-ening component must be used to suppress the shock ofthe motor. If all the parts are properly fabricated, assembly should be

simple. The next step would be to route and connect themotor, controller, batteries and charger. To prolong the lifes-pan of the batteries, it is important to maintain the batterieswhile they are not in use. Allowing lithium-based batteries tofully discharge will ruin the cells.

TestingThe last phase entails testing the powertrain, charging and

brake system. Testing the powertrain starts by lifting the vehi-cle off the ground to verify that the motor can rotate thewheels. At this point, it’s important to keep an eye on theamount of current the motor is drawing. The controller willdictate the amount of current in the system. Due to counter-electromotive force, it’s normal for the motor to draw highercurrent when accelerating from a stop and decrease as themotor’s rotational speed increases. Diagnosis of the controllerand motor must be performed if the motor exceeds the ratedcurrent draw. It’s also important to keep an eye on the amount of current

the system is drawing when testing the charging system.Absorbed glass mat (AGM) and lithium-based batteriesrequire a specific type of charger that monitors charging cur-rent. The system should taper charging current as it reachesmax capacity and each cell should fully charge at the samerate. Unfortunately, overtime each cell will deteriorate at dif-ferent rates. The result is that each cell will fully discharge andrecharge at different rates. This imbalance within the batterypack can decrease total capacity. Furthermore, the imbalance will cause the charging system

to either over- or undercharge some cells in comparison tothe other cells and cause the battery pack to fail. There areservices specifically targeted for the hybrid market to recondi-tion battery packs by balancing all of the cells. Current isdrawn from each cell, pulling the voltage of each cell down tothe same level, and charging each cell to max capacity basedon each specific cell status. This reconditions any deficientcells to be on par with the rest of the battery pack. �

Continued from page 14



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According to its designers,the Jeep Cherokee Dakaris the most extremeCherokee ever. The vehicle made its

debut on the trails andrugged terrain at theEaster Jeep Safari inMoab, Utah in April.Now in its 48th year,

the Easter Jeep Safari isattended by thousandsof die-hard off-roadenthusiasts looking toenjoy a week of seriousoff-roading on some ofthe country’s most renowned trails. There, they got to witness the

Dakar concept’s silver steel satingloss exterior skin, strikingly setoff with flame red graphics thatencircle the window and wraparound the black hood graphic. The Trailhawk 17-inch polished

satin clear coat wheels feature twolarge flame red pockets, along withthe with the Cherokee nameplate.Front-end features are enhanced by

two prototype inserts on the tradi-tional Jeep seven-slot grille, as wellas through a prototype lower fasciatrim. Cherokee Dakar is fortified for off-

road action, equipped with JeepPerformance Parts rock rails, an oilpan skid plate, front suspension skidplate, two-piece fuel tank and under-body skid plates.Cherokee Dakar’s wheel openings

have been modified in order toaccommodate larger 33-inch

BFGoodrich MudTerrain tires. Therough-and-readylook rises witha prototypeJeepPerformanceParts lift kit,and additionalsuspension

modifications help make it themost extreme Cherokee yet. And the prototype wider

fender flares with riveted boltsgive a tougher appearance andalso accommodate the widertrack and larger tires. Cherokee Dakar’s crawl ratio

is 48:1, and estimated approachand departure angles are 32 and39 degrees, respectively.Inside, Katzkin leather

black seats with “MachinedGunmetal” inserts areheightened with Header Redstitching, which is also found

on the steering wheel, armrest andshift boot. “This year, we’re showcasing a

combination of Mopar and JeepPerformance Parts on our vehicles foroff-road enthusiasts to see a varietyof customization and personalizationoptions,” said Pietro Gorlier, presi-dent and CEO — Mopar, ChryslerGroup LLC’s service, parts and customer-care brand. “Since 2002,Jeep and Mopar have teamed to create more than 40 unique conceptvehicles for enthusiasts who attendthe popular Easter Jeep Safari.” Although the concept vehicle was

powered with the 3.2L V6 stockmotor, the Jeep/Mopar crew didtweak to the exhaust to make theDakar purr like a mountain lionwhen the gas was applied. Whichwas fitting, given the location of theannual event. �

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By Ed Sunkin, Editor

Tomorrow's Tech, August 2014

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