MACS Service Reports is the offi cial technical publication of the Mobile Air Conditioning Society Worldwide, Inc., P.O. Box 88, Lansdale, PA 19446. The material published in MACS Service Reports expresses the views of the contributors and not neces-sarily that of MACS. Every attempt has been made to ensure

the accuracy of the content of MACS Service Reports. MACS, however, will not be responsible for the accuracy of the informa-tion published nor will MACS Worldwide be liable in any way for injury, labor, parts or other expenses resulting from the use of information appearing in MACS Service Reports.

October 2012 1 MACS Service Reports

© Mobile Air Conditioning Society Worldwide

“Radiator” Shutters When there�’s enough ram air ow through the front end heat

exchangers�—radiator, condenser, oil coolers, turbo air charge cooler, etc. �– closing off part of the front end can improve ve-hicle aerodynamics, which contributes to both real-world fuel economy and provides a CAFE bene t (Corporate Average Fuel Economy). It�’s done with venetian-blind-like shutters con-trolled by a linkage system to an electric motor, and although not new (Mercedes has used it for many years, and so have heavy trucks, but not for aerodynamics), it was considered a premium cost item that makers of lower-priced vehicles couldn�’t justify. But with the need to meet stricter CAFE, carmakers now con-sider radiator shutters cost-effective, and you�’ll see them even on economy cars like the Chevy Cruze. Typically, the computer closes the shutters at about 35-38 mph. A technician probably won�’t get a complaint based on shutters sticking open, but if they stick closed, the engine likely would run hot. There are trouble codes for system failures.

A signi cant exception to the simple description has already appeared, on the 2013 Ram 1500 pickup, where the shutters are opened or closed according to a sophisticated strategy that also considers engine and transmission oil temperatures, along with coolant temperature; and the shutters may stay closed to as low as 10 mph. The reason is Chrysler discovered that using the shutters to help control uids�’ temperatures is a signi cant part of engine thermal management, and may even be eligible for ex-tra EPA credits on CAFE. The more complex operating strategy is unlikely to change the diagnostics, because its primary effect is on fuel economy, and a relatively small percentage, not easy to measure by a shop technician.

In terms of physical location, the shutters are �“somewhere�” at the front of the bank of heat exchangers (condenser, radiator, oil coolers, charge air cooler). The shutters assembly could be part of a front air intake shroud very close to the condenser or lower down at an air inlet or air ow directional duct. If the engine has a turbo, you�’re almost sure to see a shutters system, but on many non-turbo vehicles as well (Figure 1).

Active Transmission Warm-upThe idea is simple: heat the transmission oil with engine cool-

ant to warm up the oil quickly, so the transmission pumps the oil more easily than when it�’s cold. The same basic idea applies to cold engine oil, and active engine oil warm-up is also on the EPA list of items for which car companies receive emissions credits that help with CAFE.

By Paul Weissler, MACS Senior Technical Correspondent October 2012NEW HVAC/COOLING SYSTEM TECHNOLOGIES – Some Already In Production, Others Very Close

Figure 1: Grille shutters are showing up on more vehicles. This set, on the 2013 Ram 1500 pickup, is just in front of heat exchangers, a most ef cient location.

PART 2 OF A 2-PART SERIES TO KEEP YOU TECHNICALLY INFORMEDLast month�’s MACS Service Reports was entirely de-

voted to informing you about new HVAC and engine cooling system technologies that you�’ll be seeing soon

(if some, not already). This issue will continue that theme, then switch gears to cover a change in coolant at Chrysler.

ALSO INSIDE THIS ISSUE:BIG CHANGES AT CHRYSLER ...................................................................................................................................................... 5

October 2012 2 MACS Service Reports

Just because an idea is simple doesn�’t mean that it�’s simple and/or cheap to execute. You know the transmission already has an oil cooler, to keep the oil from overheating. So it takes a fairly sophisticated system to permit fast transmission oil warm-up, and yet, not add so much heat that the cooler can�’t do its job. Also important: you don�’t want to use so much heat from the engine coolant that the performance of the heater core for warming the passengers is compromised in cold weather. As a result, Ford �– which uses the system on a few new cars including the Taurus, employs a speci c heat exchanger, and two bypass valves which are computer-controlled (Figure 2).

The ATWU (automatic transmission warm-up) heat exchang-er is a plate- n design, much like the engine oil coolers built into the oil lter housing adapter on many cars. Because it uses en-gine coolant as the heat exchange uid, it makes the transmis-sion uid operate at almost the same temperature as the engine.

The ATWU bypass valve is controlled by the powertrain com-puter, with inputs for outside air temperature, coolant tempera-ture and transmission oil temperature. It can disable the system (bypass the ATWU heat exchanger) if the hot coolant is needed for cabin heating, which would occur at cold ambients (close to zero degrees F). At warmer ambients the ATWU circuit is open for transmission oil warming as soon as the transmission is put into drive.

The auxiliary cooler for transmission oil bypass valve works both as a thermostat and a valve, opening when the transmis-sion oil is quite hot and needs ow through the auxiliary (trans-mission oil) cooler. This cooler is an oil-to-air type and on Taurus and Flex is a combination unit with the condenser.

Dual Action Compressor Although we think of air conditioning as purely a cooling

mechanism, you doubtlessly are familiar with reversible sys-tems, i.e. heat pumps. They�’re widely used in households to pro-

vide A/C in summer and more ef cient heating than simple re-sistance heaters in winter, just by reversing the cycle. Resistance heating provides about 3400 BTU per kilowatt, whereas the greater ef ciency of the heat pump provides 2-3 times the BTUs for the same amount of electricity, depending on the choice of the �“cold�” side of the system. If it�’s deep underground, below the household frost line where the temperature is 55�–60 degrees F, even on the coldest winter day, there�’s a lot of heat that can be �“extracted�” (Figure 3).

That�’s the idea behind a heat pump for an EV, or even a diesel,

Figure 3: This is a Delphi heat pump type climate control refrigeration/liquid coolant module �– self-contained under the hood, that uses valves to tap into the hot or cold sides of an air conditioning system, so it can perform dual function �– and because of its underhood location, use a highly-ef cient (even if ammable) refrigerant. The chiller is a heat exchanger that combines an evaporator (note location following the expansion valve) with a coolant chiller to chill the cool-ant, which then is circulated through an under-dash heat exchanger for cabin A/C. The condenser transfers heat to the �“radiator�” coolant, which for winter heating can be pumped (by the water pump) to an under-dash heater core. Two under-dash heat exchangers are required to provide effective defogging.

Figure 2: The Ford Automatic Transmission Warm-up System (ATWU) is controlled by the powertrain module, which operates a bypass valve (closing it if necessary) to allow transmission oil to ow through the ATWU oil-to-coolant heat exchanger, so transmission uid warms up quickly and operates at temperatures close to engine coolant. It also helps lower uid temperature, by working with the transmission oil cooler. If necessary, the powertrain computer opens the solenoid-type bypass to prioritize coolant ow through heater core for cabin comfort in extremely cold weather. A very similar system is used on the new Ram 1500 pickup.

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October 2012 3 MACS Service Reports

which today may use a diesel-oil- red heater for cabin comfort. With a car, however, the system operates primarily at ambient temperature, although with an electric vehicle, there also may be some amount of heat recoverable from the battery pack and inverter, even in winter. The General Motors EV-1 used a heat pump, and so did the prototype models of the Toyota Prius plug-in hybrid, although the production model has PTC heat-ers.

A novel approach was shown by Delphi, a system in which the refrigerant ow is in one direction (conventional A/C) but the condenser is combined with an antifreeze/water coolant heat exchanger to absorb heat from the refrigerant for cabin heat. For A/C the refrigerant ows through an expansion valve into another heat exchanger called a chiller, where the refrigerant chills an antifreeze/water mixture that ows to an under-dash heat exchanger. This system is called �“secondary loop,�” because the refrigerant owing through the expansion valve doesn�’t ow to an under-dash evaporator. Obviously it�’s less ef cient to use the chiller, an extra heat exchanger, but possibly with a more ef cient refrigerant, it could balance out. Because the system is completely underhood, a high-ef ciency (though ammable) refrigerant would be acceptable. The sys-tem is integrated into a compact module with metal lines and a near-hermetically sealed compressor.

Automatic DefogMany cars, particularly premium

models, are being equipped with au-tomatic defogging, which turns on when a sensor indicates the windshield is fogging. Usually a sensor is at or close to the windshield, and it checks humidity level and glass temperature. A body computer calculates the dew point at that location, and if it�’s appar-ent that the windshield is starting to fog, it turns on the A/C and switches the system to defrost. Under some con-ditions, this may affect the comfort of the passengers, but it�’s the price of a safety system. Yes, motorists could hit defrost themselves, but windshield fogging complaints turn up in motorist satisfaction surveys, so the automatic defog system has been well-received �– if it works well.

One of the more sophisticated de-signs rst appeared on the Hyundai Genesis and now is on the Elantra, using a new sensor attached to the windshield with a temperature probe against the glass for very accurate temperature measurement, and close-enough measurement of humidity. The Hyundai system also has a modi ed HVAC case, so the defrost door oper-ates independently of the other mode

actuators. This permits some separation of the control func-tions, so the system can provide separate temperature con-trol for the cabin and the blower fan air ow.

Exhaust Heat Exchanger

Figure 5: Schematic view of the Prius exhaust heat recovery system. Inlet and outlet coolant hoses attach to the heat exchanger within front exhaust pipe section. A coolant temperature switch in the circuit con-trols the exhaust actuator and its ap valve. When the actuator closes the valve, exhaust gas recirculates around the coolant heat exchanger, transferring exhaust heat. When the exhaust temperature is too low, the ap valve is opened and the exhaust goes directly into and through the piping, muf er and tailpipe.

Figure 4: The new Toyota Prius plug-in hybrid has a coolant heat ex-changer built into its exhaust pipe right after catalytic converter. It�’s there to provide hot coolant to heat the exhaust port after an engine restart to light off the catalytic converter.

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October 2012 4 MACS Service Reports

Even after exhaust gas leaves the catalytic converter (where it had to be hot to cause the catalytic reaction that reduced emis-sions), it�’s still hot. Capturing heat from that exhaust before it exits the tailpipe is a way to improve ef ciency. There has been work with using the exhaust heat to produce electricity. There isn�’t a huge amount of heat available, but there may be enough that can be collected with an ef cient heat exchanger, and at some point perhaps, used with a thermal exchange device (there are several possibilities) to produce electricity. EPA provides a CAFE credit (Corporate Average Fuel Economy) for such a de-vice.

In the meantime, exhaust heat can be collected and used in other ways. One would be to warm up engine and/or transmis-sion oil, which also carries a CAFE credit. The purpose of the one on the Toyota Prius, however, is to reduce emissions (yes, even on a hybrid). There is an exhaust heat-to-coolant heat exchanger in the exhaust pipe after the catalyst (Figures 4, 5). The heat ex-changer raises coolant temperature when the heat is needed. The hotter coolant can aid cabin heating a bit, but the primary bene t is to circulate around the exhaust valves when the en-gine is shut off, as during a highway coast and is about to restart. So when the engine is restarted, the gas owing through the exhaust port, which initially wouldn�’t be all that hot, is given a temperature boost. It then ows through the catalytic converter, �“lighting it off�” to promote catalytic action for lower emissions. The previous generation Prius had a �“Thermos�” bottle that held about three liters of hot coolant for the same purpose.

Super Compact HVACInasmuch as the HVAC case ts under the dash, saving space

might not seem so important, but it is. On the new Scion IQ, for example, the 10-foot car would be a really tight t in both back

seats. But the DENSO case integrates the blower section into the center section with the evaporator. So the right side of the dash-board is just ductwork, and takes so little space, the right front seat can be moved well forward and still have plenty of passen-ger room. That means the right rear passenger also will have lots of legroom (Figures 6, 7).

Figure 7: Air intake (front) view of the physical HVAC system, which mounts behind center stack and has only ductwork added to side regis-ters. It is 20% smaller in volume than a conventional system and has a smaller, high-ef ciency blower.

Figure 6: Cutaway illustration of Scion IQ case shows the blower integrated into the case.

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October 2012 5 MACS Service Reports

BIG CHANGES AT CHRYSLER

You may know that the Fiat 500 uses an organic acid technology inhibitor (�“OAT�”) antifreeze formula with an orange dye, and that it could be confused with the low-silicate �“HOAT�” G-05 (hybrid OAT) in all Chrysler-built products�—also with orange dye. Now there�’s a big change that will make things even more confusing: the entire Chrysler U.S. product line is being changed over to an OAT�—and with still another color dye (purple).

There is a problem with the early models, which like the OAT in the Fiat 500, have an orange dye (Figure 8) because

it�’s the same product as in the Fiat line, we�’ve been told�—a temporary situation that since has been changed. That�’s the same color dye as the low-silicate HOAT (Zerex G-05) that Chrysler has been using, although all other supplies of G-05 that we�’ve seen (Ford, Mercedes, for examples) have yellow dye. Dye colors mean nothing in terms of the corrosion inhibitor formulas. However, in either case, neither Chrysler nor Fiat is using one of the current Dex-Cool formulas, but the situation is a bit complicated, as you�’ll see. Let�’s begin:

At the time (late 1990�’s) when Chrysler switched from �“conventional American�” antifreeze to G-05, it wanted to distinguish it from the gold/yellow dye of the Prestone brand of conventional American antifreeze (high silicate, plus phosphate and borate), despite the fact that orange DexCool was already on the market.

Chrysler had been the last of the U.S. makers to be installing a silicate-containing antifreeze (that G-05) on the assembly line, and now it joins the other Detroit au-tomakers in the switch to an OAT. There�’s a change to

purple dye underway that will simplify the identi cation issue, and it seems likely it will be made across the board, as soon as 2013 production hits full stride. We just drove a 2013 Ram 1500 pickup, and it had the new purple dye antifreeze. The reservoir is buried, and the radiator ll is black, so we couldn�’t take a photo that would mean much even if MACS Service Reports were in color.

We�’ve cited the major issue with the OATs: they take 5000 miles to produce the protective oxide coating on the walls of the cooling system, and that can be a problem, as we explain later in �“How Mercedes Does It.�”

There�’s still a very important difference in the OAT formulas �– that is, what Chrysler uses is very different (not only from Fiat�’s formula) from any of the DexCool formulas in General Motors and Ford products. There apparently is no signi cant chemical incompatibility, but we�’ll explain why the Chrysler formula and Fiat formula are different from DexCool and DexCool-type brands in a very important way.

So with these orange or purple dye �– but NOT Dex-Cool-type �– antifreezes in 2013 Chrysler products, you do have to be careful when you top up or at some point do a ush and ll. The OAT and previously used G-05 HOAT (Figures 9, 10) are further apart than the letter H. They

have totally different rust/corrosion inhibitor formulas, be-yond the low-silicate content of G-05. Any pure OAT con-tains no silicates or phosphates. Further, the DexCool type typically is a mixture of 2-ethylhexanoic and sebacic acids.

Figure 8: Coolant reservoir of Dodge Dart. Although MACS Service Re-ports is printed in black and white, take our word for it: the coolant is orange. And you can see the label that says �“OAT Coolant,�” but it�’s not DexCool-type. We�’ve been told it�’s the Fiat type, soon to be replaced by a purple dye antifreeze with a different corrosion inhibitor formula, from a different suppliers. We�’ve already seen the purple dye antifreeze, in the 2013 Ram pickup, so you can expect to see it in 2013 Chrysler products (except early-production vehicles).

Figure 9: Zerex G-05 is labeled a phosphate-free formula (see arrow), because the Europeans have a hard water test that results in heavy scale deposits with phosphates.

October 2012 6 MACS Service Reports

As will be discussed in more detail in the January 2013 issue of MACS Service Reports on water pumps, you never want to mix. Just a small concentration of the OAT in a HOAT system or a HOAT in the OAT system can cause major corrosion problems. There are several OAT formulas, but 2-ethylhexanoic acid, so far as we�’ve found, has always been used until recently, and 2-EHA is a controversial chemical. It softens plastics, and particu-larly has an effect on silicones, which had been used in coolant-sealing gaskets and O-rings, and for heavy-duty vehicles in some coolant hoses because of its excellent durability in high temperatures. The OATs in Chrysler and Fiat products, although measurably different formu-las, feature sebacic acid but absolutely no 2-EHA.

That doesn�’t mean Fiat or now Chrysler is using cool-ant sealing materials with silicone, just that it is con-cerned that silicone seals might be used in aftermarket replacement parts. And although its antifreezes don�’t contain 2-EHA, it does recognize that when topping up or ushing systems, an OAT with 2-EHA might be used. That�’s apparently tolerable, a Chrysler engineer told us, so long as cooling system seals are silicone-free.

There are many organic acid inhibitors and different formulas. DexCool labeling refers to a performance test, not a composition formula, although silicates and phos-phates can�’t be used. So the organic acid contents (and other corrosion inhibitors) between brands may be dif-ferent. Although typically 2-EHA is used because of its cost-effectiveness, it actually isn�’t required for DexCool.

At this point we don�’t have a breakout of all the in-gredients in the Fiat and Chrysler formulas, beyond the use of sebacic acid as the primary inhibitor (in a cocktail with two other organic acids for the Dart), and absence of 2-EHA, silicates or phosphates. Almost all Asian makes use phosphate, and low-silicate still is used by Mercedes-Benz. And there even are DexCool-compliant formulas that just use the 2-EHA with other inhibitors, such as molybdate. In any case, if it�’s a DexCool formula, it�’s compatible with any other DexCool formula, but when it comes to the Chrysler and Fiat formulas, they have the advantage of no 2-EHA. And you should want to pre-serve that advantage when topping up or doing a ush-and- ll.

But you can�’t really be 100% positive about aftermarket brands, because they often do NOT have the DexCool la-

bel, to avoid having to pay a royalty to General Motors. However, if it�’s a major brand and it�’s called an OAT, there should not be a compatibility issue of concern with a DexCool or OE DexCool type. There apparently is not a measurable compatibility issue between the Fiat and Chrysler formulas either, or those formulas and a Dex-Cool type, but we�’d be inclined to avoid anything with 2-EHA because of the potential silicone gasket or hose is-sue. The problem is that you can�’t tell by labeling in most cases, because most antifreeze jugs don�’t list all the ingre-dients. Prestone does�—its antifreeze is a DexCool type without the label and in very small print on the back of the jug, it says it contains 2-ethylhexanoate (another way to write 2-EHA or 2-ethylhexanoic acid, Figure 11).

Note: Although we�’ve often referred to GM cars�’ use of DexCool by 1994, there were a couple of ex-ceptions, such as Saturn (which phased it in a cou-ple of years later) and the Suzuki-built Chevy Aveo (Pontiac Wave in Canada), which used a convention-al American antifreeze (silicates, phosphates and bo-rate) up to 2005. But the OE coolant had a blue dye, not the American green (or Prestone�’s gold with a greenish tint).

The only Chrysler indicator for the OAT systems with orange dye antifreeze is a label on the coolant reservoir that says �“OAT Coolant�” for those early models (Figure 8), and if that label ever comes off, a mistake could easily be made. We�’d say flush-and-fill with the purple stuff.

Why is Chrysler changing from an antifreeze that has been used so long (and still is in use by Mer-cedes) and so successfully. The reasons are not the same as Ford�’s.

�• It now has a formula that passes its testing for a 10-year, 150,000-mile ser-vice interval, and that 10-year number is apparently the key. Chrysler says that except for the Mercedes approach, it could not meet that specification with-out an OAT. The G-05, it said, was maxed out at 5 years, with the mileage limit at 100,000 miles, although the antifreeze

Figure 11: Prestone jug lists both �“2-ethylhexanoate�” and �“neodecano-ate�” (another organic acid) among its ingredients.

Figure 10: G-05 jug doesn�’t list its silicate inhibitor, only (under �“con-tains�”) benzoate and (tetra)borate inhibitors, although the OE jug from Mercedes does mention silicate.

October 2012 7 MACS Service Reports

jug lists the product for 5 years/150,000 miles. The Chrysler antifreeze is made by CCI Manufacturing, an OE coolant supplier based in Illinois.�• Standardization between Chrysler and Fiat worldwide is not an issue. Al-though Fiat has been using an OAT that also contains sebacic acid, it is measur-ably different from Chrysler �’s, and is supplied by a different company. Fiat�’s antifreeze is from Petronas Lubricants, an OE chemicals supplier that does not market in the U.S. at this time. Although the early 2013 Chrysler products use the Fiat antifreeze, that was strictly a sup-ply decision until CCI purple product becomes available. By the time you get this issue, the purple stuff should be all you�’ll see beyond possibly an occasion-al early production vehicle.�• Satisfy environmentalists who have complained about conventional anti-freezes and their effect on groundwater if dumped. The OAT permits the 10/150 service interval for Chrysler as we not-ed earlier. So if the system isn�’t drained, the antifreeze corrosion protection re-mains functional. This is an exaggera-tion, because coolant contamination can occur from top-ups or even with less-than-optimal use of a flush-and-fill ma-chine, regardless of the OE antifreeze, as will be covered in the January 2013 issue.

The surprise is the use of the OAT with the Cum-mins six-cylinder diesel. Pitting corrosion of the Cummins cylinder liners from diesel vibration was controlled by an additive, nitrite, in the G-05 HOAT. However, nitrite can�’t be used with a pure OAT, so there goes the liner pitting protection. The apparent answer (as on GM and Ford diesels) was that engine manufacturing process was redesigned to minimize the possibility of vibration, and GM results with the Duramax diesels have been acceptable. And the pri-mary problem was with wet diesel cylinder liners, not the type used in the light/medium-duty vehicles.

How Mercedes Does ItYou may wonder how Mercedes-Benz has been

able to use a silicated antifreeze and still have a long service interval �– 15 years/150,000 miles. To get around the issue of silicate depletion (being used up) over time, it installs a silica gel packet (like you find in packages of electronics to absorb moisture). That packet, in the coolant reservoir, allows a very slow release of silicate particles to �“refresh�” the anti-freeze. And Mercedes engineering has validated this

approach, so why change? As a result, it still uses a silicate antifreeze. It�’s not G-05 anymore, but G-48, which contains sebacate and a dash of 2-EHA. And as used by Mercedes and periodically by other Ger-man makers (VW/Audi and BMW), it has a dark blue dye (as far as we can tell). Tests show it is fully compatible with G-05, although the two different dyes cause a coolant color change and may be con-fusing when you look at the reservoir. One aspect of G-48 vs. G-05 that deserves note is that it contains no nitrite, that protectant against diesel cylinder liner pitting. Of course, as noted earlier, the light-duty diesels in cars and even light/medium duty pickups don�’t have wet liners, so the value of nitrite seems to be minimal.

There seems to be a formula trend to OAT in Eu-rope, but the German makers still like some �“silicate cream�” in their �“OAT coffee,�” so to speak. Silicate inhibitors are incomparable in providing that low-mileage protection in the first 5000 miles that OATs do not, and in that regard they are especially use-ful if there are residual fluxes in the CAB (continu-ous atmospheric brazed) heat exchangers, as those fluxes can turn corrosive. No question that silicates do provide extra protection for situations like those.

So there are a number of these combinations of sili-cates and organic acids in European use, with num-bers like G-30 and G-40, and they seem to be com-patible with each other, including with G-05. So as an aftermarket choice, that G-05 should be on your shelf. If an aftermarket G-48 ever hits the U.S. mar-ket, it might replace the G-05 on your shelf, but for the present�…

And of course, you should use G-05 in those 2011 and older Ford products and 2012 and older Chrys-ler products for which it was the OE antifreeze.

In case you�’re wondering, the �“G�” stands for Glysantin, a brand name of BASF, a worldwide chemical company that dominates the European market for antifreezes. And each number represents a specific BASF formula. Zerex (Valvoline) acquired BASF�’s antifreeze business in the U.S. some years ago.

What About Asian Carmakers? The Asian brands all use antifreezes with phos-

phates instead of silicates. Like silicates, phosphates work quickly to protect the cooling system from corrosion. The Asians all use a test that rejects sili-cates, but requires something �– phosphates being the choice�—to pass their cooling system tests that require fast protection. As we�’ve noted, organic ac-ids take about 5000 miles to form the oxide on the walls of the cooling system for corrosion protection. The previous generation of Asian antifreezes, such as Toyota red, were a mix of phosphates and benzo-ate, a type of organic acid but now used in just a few

October 2012 8 MACS Service Reports

MACS Service Reports is published monthly by the Mobile Air Conditioning Society Worldwide. It is distributed to members of MACS Worldwide and is intended for the educational use of members of the automotive air conditioning service and

repair industry. Suggestions for articles will be considered for publication, however, MACS Worldwide reserves the right to choose and edit all submissions.

Unless otherwise noted, all photos/art by author.

Editors: Elvis Hoffpauir, Paul DeGuiseppiProduction Designer: Laina CaseyManager of Service Training: Paul DeGuiseppi

Mobile Air Conditioning Society WorldwideP.O. Box 88, Lansdale, PA 19446

Phone: (215) 631-7020 • Fax: (215) 631-7017Email: membership@macsw.org • Website: www.macsw.org

long-life formulas, such as in Hyundai-Kia and Zer-ex Asian long life. Most Asian formulas today, such as Toyota pink, contain sebacic acid and phosphate. Both types of Asian antifreeze are called �“phosphat-ed HOATs.�” Any antifreeze with phosphate should not be used in a system with a pure OAT.

But How Can You Tell? Sadly, not all antifreeze jugs tell you what cor-

rosion inhibitors are used. But believe us that the Asian OE brands and Zerex Asian long life all con-tain phosphate. Toyota red says �“hydrated inorganic salts�” on the back of the jug. That�’s phosphate. Zerex Asian long life just lists benzoate, an organic inhibi-tor, but also refers to �“Phosphated HOAT Technol-ogy�” on the back of the jug, so you know (Figure 12. Zerex G-05, however, just lists benzoate and (tetra)

borate, but not the silicate inhibitor that it has, a for-mula that met the OE requirements (until the Ford and Chrysler switch to OAT and the German move to G-48, which we covered earlier). Prestone lists �“2-ethylhexanoate�” and �“neodecanoate,�” another or-ganic acid.

The Parts IssueAs noted earlier in this report, it�’s important to un-

derstand that 2-ethylhexanoic acid softens a number of plastics, which can result in coolant leaks from affected gaskets and sealing rings. The most sus-ceptible plastic is silicone, and Ford decided years ago that it wouldn�’t use a DexCool formula because of its effect on sealing in the modular V8s (4.6 and 5.4-liter engines, which are now being phased out). So as we�’ve pointed out, any OE rubber parts for the cooling systems of Chrysler engines will not incor-porate silicone, and any parts from engines running with the G-05 antifreeze that did contain silicone are not going to be recommended for use with the new engines if they come in contact with coolant. So watch what seals, gaskets and hoses you take off the shelf. Just because they fit doesn�’t mean they�’ll provide durability. There�’s no problem with the OE OAT, but we suspect that any 2013-model onward Chrysler cooling system flush-and-fill is more likely to be filled with a DexCool-type OAT (or even G-05) than the new 2-EHA-free purple stuff.

There also have been indications over the years that some other elastomers, including some forms of nylon and neoprene (not all) might not be so durable in contact with OAT coolants. So here again, watch what you install. Chrysler has been running durabil-ity tests on dynamometers for the past year, along with road testing, just to validate the parts it is using and recommending. If you see a cooling system part is a carryover, that�’s a sign it isn�’t made with a ques-tionable elastomer.

What about copper-brass in a replacement part? All these antifreezes, including the HOATs and the OATs, contain a copper-brass inhibitor as a �“just in case.�” So that�’s not an issue.

Figure 12: Although phosphate is not listed among the ingredients in Zerex Asian long life, on the back of the jug there are these notes about �“Phosphated HOAT technology,�” and �“Silicate and Borate Free.�”