ust when you thought you hadautomotive a/c service figuredout, it’s ready to enter an entirelynew era, with new equipment,new techniques and, in the nextfive years, apparently one or

more new refrigerants.The chapters of the story have been

unfolding each year at the conventionand trade show of the Mobile Air Con-ditioning Society (MACS), and everytime we look, the story seems to takesome unexpected turns. Last year wediscussed the issue of refrigerant con-servation, the problems of recovery andaccurate charging, and leak detection.Did we solve these problems for you?

Maybe not. But while there’s goodprogress to report, a number of newcomplications have entered the picture.

R-134a still seems to have a solid fu-ture in this country, but increasing de-mand and environmental concerns have

led to a lot of changes. The problems aremounting as fast as we can take notice ofthem, starting with the refrigerant itself.

Buying Pure RefrigerantBecause many third-world countrieshave been converting from R-12 to R-134a, demand is up and new plantshave been built in China. Questionshave been raised about the purity of therefrigerant and the quality as delivered,particularly from China. So what are wetalking about?

While there are engineering stan-dards for refrigerant purity, such asfrom the Airconditioning and Refriger-ation Institute (ARI), as well as the re-cycling standards from the Society ofAutomotive Engineers (SAE), a poorproduction process will result in unac-ceptably high levels of certain impuri-ties, which can affect a/c system materi-als and pressures, and possibly create

blockages. If impurities are kept below40 parts per million, they’re not a con-cern. Also at issue is ingestion of mois-ture (should be under 10 ppm) and air(below 1%), both of which are post-production concerns.

You can’t check for impurities or thepresence of moisture with a refrigerantidentifier; a lab test is required. And ittakes a premium identifier to detect airof 2% and lower. However, if you peri-odically buy a jug of bargain R-134afrom other than the most trustedsources (which we caution against, bythe way), it’s still a good idea to check itwith an identifier. You might find out itisn’t R-134a, but something else.

One visual tipoff might be the colorof the R-134a jug. It’s supposed to bepowder blue, not white (R-12) or green(R-22). But a MACS test of a jug at amilitary installation (and who has moreelaborate purchasing systems than the

28 April 2006

THE EVOLVING A/CSERVICE PICTURE

BY PAUL WEISSLER

R-134a has been with us for more than 10 years,

and could continue as the U.S. refrigerant of

choice for years to come, if updated tools and

service techniques are properly implemented.

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military?) showed that a blue R-134ajug actually contained R-12.

The Chinese refrigerant issue led twoMACS trade show exhibitors to focuson the purity question. Contake Chemi-cal Group U.S.A., a marketer of Chi-nese-made R-134a under the Bluestarbrand, showed laboratory tests for a re-cent batch tested in China that revealedimpurities at 38 ppm, just under the 40-ppm limit, low moisture (6 ppm) andlow air content (.7%).

Arctic Air posted signs at the showsaying that although its jugs of R-134acome from China, the R-134a itself isproduced in Japan and shipped to Chi-na where the jugs are made and filled.The U.S.-tested lab results showed theycontained 4 ppm impurities, 7 ppmmoisture and just .5% air.

So stick with known suppliers, anddouble-check with a refrigerant iden-tifier.

tests for fluorescence. When you’rebuying additives or dyes, look for label-ing on the container that tells you itmeets the appropriate SAE standard,and look for a known brand.

Compressor Oil ConfusionAt one time we thought we’d get downto a single compressor oil for all R-134a systems, but a number ofthings—including the increasing popu-larity of gasoline/electric hybrids—have helped muddy the picture. In-deed, General Motors once said a sin-gle PAG oil could be used for small ad-ditions on all its compressors except afew older designs. Now GM has goneeven further, saying that its “universaloil”—a PAG of 46-53 Centistokes(Cst), ACDelco No. 88901445/10-5026—can be used in every system exceptthe old A-6 and the Radial-4. In those,ACDelco No. 15-118 (a PAG in the

29April 2006

‘Do No Harm’ AdditivesShow exhibitors also noted J2670, a newSAE standard for additives and flushingsolvents that may be poured into the a/crefrigeration system. Although flushingsolvents are removed with an air purgeand by evaporation, there’s no assurancethat some solvent doesn’t remain in thesystem’s nooks and crannies.

This SAE standard specifies testsonly for compatibility—the objective isto “do no harm.” It does not mean thatthe additive performs as advertised, oreven does anything beneficial at all.Some of the additives sold for “im-proved cooling” have raised questions asto their effectiveness. But if they’re cer-tified to J2670, you’re assured theywon’t cause deterioration inside the sys-tem, including to sealing materials.

This standard does not have tests fortrace dyes; they’re covered by a sepa-rate standard (J2297), which includes

range of 125-150 Cst) is recommended.Unlike the days when all GM vehi-

cles had Delphi compressors, today youalso may find GM models with Denso,Sanden, Mitsubishi, Visteon and Zexel(a rotary vane type that was used on theSaturn L). So that gave GM some in-centive to standardize where possible.

Hey, what about the GM/Delphi V-5and V-7 compressors, and those light-weight Delphi axial six-cylinder units(DA-6, H-6, HU-6, HT-6)? They seemto be covered by the new 46-53 PAGuniversal oil. However, most shops thatdo a/c service these days stock at leasttwo, maybe three PAGs: 46-53 Cst and125-150 Cst, plus perhaps 100 Cst. Soyou may want to take this approach:

For Delphi V-5, V-7, Radial-4, DA-6and those lightweight H-series axial six-cylinder compressors, use the 125-150Cst oil if the compressor is old and noisybut still serviceable, to help reducenoise and vibration. If you’re installing abrand-new compressor other than A-6and Radial-4, you can use the 46-53 CstPAG. For other applications:

•Ford (all models) and Chryslerproducts with Denso compressorsand Sandens that carry an SD-15 oilrecommendation on the underhoodlabel: 46-53 Cst PAG.

•Chrysler products with Sandenseven-cylinder compressors that carryan SD-20 oil recommendation: 100Cst PAG.

•Japanese and European cars withSanden compressors (scrolls and sev-en-cylinder with an SD-15 spec): 46-53 Cst PAG.

•European cars with Denso com-pressors: 46-53 Cst PAG.

That would seem to cover the water-front, but it really doesn’t. Denso, forexample, makes Toyota-application

compressors that are not used by GMand that have requirements for specialadditives. The old R-12 DENSO “TV”rotary vane (Tercel/Paseo primarily), re-quires a synthetic oil labeled ND-7, notmineral oil (labeled ND-6 as used inother Toyota R-12 systems).

Most Toyota/Denso systems with R-134a use ND-8, or an equivalent ISO46-53 Cst PAG oil. However, the sys-tems with the R-134a version of the TVrotary vane use ND-9, a specific PAG.And there’s one more PAG: the Densocompressor in the RAV4 electric vehicle(very few produced and sold) uses an-other special PAG oil, ND-10. This oilobviously was chosen for the special op-erating cycle of air conditioning withthe electric drive, and should not beused in any other electric, including allthe Toyota hybrids.

Do we really need all those specialDenso oils for Toyota? It comes downto what Toyota certified. Generally,these oils are close to regular oil, butwith special additives so the compressorgets through the Toyota endurance andsmooth-performance tests it apparentlyjust missed passing with ND-8. Thesespecial situations do occur.

When it comes to the hybrids, thereare even more choices, and the RAV4

30 April 2006

THE EVOLVING A/C SERVICE PICTURE

This is a variable-displacement compressor that’s beingused in the new Dodge Caliber (the Neon’s replacement).The compressor, which does not have a clutch, changesdisplacement according to a complex computer strategythat estimates cooling load. That’s a more energy-efficientapproach that’s similar to ones being adopted by manu-facturers worldwide to improve vehicle fuel economy.

The SAE work group on leak detection made many tests ofexisting electronic leak detectors, such as this false-trig-ger test with upholstery cleaner. As a result, the pro-posed new standard will require each detector manufac-turer to specify which chemicals may cause its unit tofalse-trigger. Detectors would be required to resist false-triggering from common automotive oil fumes.

You can’t expect a refrigerant identi-fier to measure impurities, but somepremium models (such as this Neu-tronics unit) can measure air, whichyou don’t want to be paying for whenyou buy a jug of R-134a. In this case,the refrigerant is all R-134a, but 5%of the jug is filled with air.

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electric’s ND-10 PAG oil is not one ofthem. Prius models up through 2003use the same ND-8 (or ISO 46 equiv-alent) as in nonhybrids. However,2004 and later models have an electric-motor-driven compressor, so the a/ccan run with the engine off. This setupis also used on the Toyota Highlanderhybrid and Lexus RX 400h, and re-quires a polyol ester oil.

But isn’t polyol ester the oil that wasdetermined to be inferior to a goodPAG? Yes, but with an electric motor inthe compressor, the oil has to have high“resistivity,” so there is no current leak-age from the 200-plus volt system(which could be a safety hazard for atechnician). It takes an ester to providethat, and each one is a specific formula-tion.

The same issue exists for the newestHonda Civic and Accord hybrids.Their compressor is a dual-drive—both belt and (with the engine stop-ped) electric motor. So that compres-sor—a Sanden design—also requires aspecial ester, but it’s not the same asthe one used for the Denso.

Another “special” oil isn’t quite sospecial: The 2005 Toyota Tacomatrucks have a Delphi axial six-cylindercompressor that calls for a DelphiNo. RL897 oil, which has a viscosityof ISO 61. Here again, this was aDelphi-certified oil for its factory-fillfrom its long-time oil supplier, andToyota just picked up the Delphi oilrecommendation. Right now, the ve-hicle is so new you won’t be able tobuy the stuff (even from a Toyotadealer), and we don’t know when or ifyou ever will. GM is using a similarcompressor with the 46-53 Cst PAG,and we’d say that oil should work.But if Toyota does decide to putRL897 into dealer stock, we’ll let youknow.

The premium “closed-end” typePAG oils (referring to the chemicalstructure) widely used as originalequipment originated in Japan andhave been sold here exclusively byApollo America. Now there’s a com-petitive line from Castrol, marketed byTechnical Chemical Co., that was in-troduced at the MACS trade show.

Tools, Techniques & PartsLeak detection continues to be a popu-lar topic at the MACS convention, par-ticularly with the continuing trend to-ward smaller charges. We talked abouta possible new SAE standard in lastyear’s report. It has since been drafted,and now is going through the SAE re-view process. If it takes effect, it will re-quire a new generation of ultra-sensitiveelectronic detectors with greater resis-tance to false-triggering, including in afume-contaminated underhood envi-ronment. Although there was talk aboutspecifying detectors that took staticreadings (point & shoot), the SAE workgroup decided to continue with themuch tougher moving-probe test thatsimulates a technician at work.

The current test requires 1⁄2-oz. leakdetection with a probe moving pastthe leak at 1 to 2 in./sec., from a 1⁄4-in.distance. The proposed test in thedraft version of the new standard re-quires detection of leaks down to 1⁄7oz. (70% smaller), from a gap of 3⁄8-in.(a 50% increase) at 3 in./sec. (again, a50% increase).

However, don’t try to get by with acheap detector, while waiting for a next-generation unit to meet that standard ina year or so. MACS member shops withtoday’s premium detectors report goodresults in finding leaks that other shopswith the cheap detectors could not find.The good detector you buy now willcontinue to be useful even years fromnow. Also, follow the manufacturer’s in-structions, which say, basically: 1. main-tain the detector; 2. adjust it carefully; 3.when the detector sounds, note the lo-cation and keep going until you’vechecked the entire system.

So what place in leak detection doestrace dye have? Well, if the system al-ready contains trace dye, using an ul-traviolet light is a good way to look fora leak. Some manufacturers install iton the assembly line, althoughChrysler has dropped it and Toyotadoesn’t recommend putting anythingin the system besides refrigerant andoil. Or a technician may have installedit to find a previous leak. The tracedye manufacturers have been makingtheir UV lamps far more compact, sothey fit into tight quarters and, using

32 April 2006

THE EVOLVING A/C SERVICE PICTURE

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PAG oil, which is recommended for engine-driven compressors, gets a Nowhen it comes to electrically operated compressors used in some Toyota andHonda hybrids. And if you look underhood, you may even find a warning labelthat requires use of only a specific oil, which is a polyol ester.

LEDs, produce much brighter lights.One dose of dye is enough. Adding ex-tra shots of dye not only won’t help,but because dye changes the viscosityof the oil, excessive use can adverselyaffect compressor life.

Some smaller leaks—such as one atthe evaporator—just won’t alwaysshow up easily with today’s electronicdetectors. If you can gain access to theevaporator condensate drain, the UVlight may illuminate a dye trace at thebottom of the drain tube. If there’s notrace there, you can try inserting aborescope up the drain tube to inspectthe evaporator core.

The truth is that evaporators aretough to inspect because of their loca-

tion. So before you just remove one be-cause you can’t find a leak elsewhere, atleast disconnect the tubing connectionsunder the hood, connect a vacuumpump and perform a vacuum decay test.This test isn’t a sure thing, but it approxi-mates the Ford warranty requirements.

MACS recognizes the problem ofevaporator leak detection, and propos-als for new procedures have been ad-vanced. There’s nothing specific to re-port now, but we assure you the issueisn’t being ignored.

Compressor shaft seal leaks are an-other problem area, because they’reusually significant only with the systemrunning, when an electronic detectorcan’t be used. Some technicians report

good results by running the system withthe electric fan disconnected to buildup high-side pressures, then shutting itdown and checking with an electronicdetector around the clutch air gap andclutch hub nose.

Trace dye also may help find shaftseal leaks. However, you may have topull the clutch to find a dye trace in theshaft hub area.

Don’t forget to check all the com-pressor joints for leaks, not just theshaft seal. And if you find a numberof small leaks on a system, replace allthe seals involved. At the MACSshow, Santech featured packs to makesure you have all needed seals. TheSantech line also has special packs if

34 April 2006

THE EVOLVING A/C SERVICE PICTURE

Tracer Products’ new professional trace dye kit featuresits powerful Optimax flashlight-type LED ultraviolet lamp,six a/c dye capsules and, to the right of the case, twobottles of dye for other uses—one for automotive oils andone for extended-life orange-dye coolants.

Bright Solutions introduced this new kit at the MACStrade show. It contains a subcompact flashlight-type LEDlamp, dye capsules, syringe-type injectors and adapterhose, plus a spray bottle of dye clean-off solvent.

This UView kit, which was also shown at the MACS trade show,contains its Spotgun Jr. caulking-cartridge-type dye injectorand Phantome-Lite thin, small flashlight-type LED lamp.

Checking for a leak from a compressor shaft seal is a toughproposition, but the best time to do it is right after engineshutoff. You can probe with an electronic detector at the com-pressor nose and at the bottom of the clutch at the air gap.

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you find the leakage is at the service valves, as it often is.If you find a leaking O-ring at a refrigerant line joint, replac-

ing it is not always simple. If it’s a tubular fitting, just unthreadit. If it’s a spring-lock coupling, you surely have one of the sim-ple plastic tools for it. But many manufacturers are using snap-together plastic couplings to hold the joint, and these take spe-cial tools to open. Classic Tool Design markets a simple screw-driver-type tool for the couplings used by Toyota. At theMACS show, AirSept introduced a kit that includes tools for

VW and Mercedes vehicles. AirSept also said it intends togradually expand tools coverage for these couplings. Trying topry open a coupling with a pick or other jury-rigged setupcould break the coupling, which means a “Do you have one inthis size?” call to the dealer.

When you find and fix a leak with an electronic detector ona system without trace dye, it’s a good idea to inject a dose as afinishing touch. That can give you a head start if the systemdevelops a new leak later on.

36 April 2006

THE EVOLVING A/C SERVICE PICTURE

Santech Industriesfeatures a line ofa/c system sealsin convenientpacks. Shown hereon display at theMACS trade showis the company’sline of individual-make seal kits.Santech also sellsmodel-specificservice valve kits.

With plastic snap-together couplings

holding morerefrigerant jointstogether, AirSept

introduced its firstkit at the MACS

trade show. The toprow of four are for

snap-ringcouplings, the

center pair are fornew Volkswagens

(primarily theTouareg) and the

bottom tool is for aMercedes coupling.

The European plan to phase out R-134a starting in 2009-11 is just a

few years off. The intent was to con-vert to carbon dioxide (CO2), an obvi-ous refrigerant (it’s dry ice) that hasthe most benign possible globalwarming implications. However, usingCO2 requires an ultra-high-pressuresystem, a difficult and expensive engi-neering issue. So despite a large in-vestment in CO2 a/c, the governingbody of the European Union (a con-sortium of most European countries)left room to allow use of alternativerefrigerants with slightly higher glob-al warming numbers. The known al-ternatives were flammable, andtherefore were given little chance.DuPont and Honeywell, however, re-cently announced that they have de-veloped and would produce safe newrefrigerants that would meet the lowglobal warming requirements.

All this may get confusing, andyou may wonder what you shouldbe doing. Here’s our best take onthe situation:

•Adopt the Las Vegas line andthink, “What happens in Europe staysin Europe—for a long time anyway.”The U.S. and the rest of the world arecommitted to tightening up R-134asystems and greatly improving theirefficiency—nothing about that haschanged in the last year. The neededchanges all have been identified, andsome already being used are cost-effective for both the vehicle makersand motorists. They’ll pay for them-selves in better fuel economy. Eventhe Europeans are adopting many ofthem, because they realize that a fullchangeover to another refrigerantmay start as late as 2011 and not befinished until 2017.

•It’s unlikely to matter to the U.S.what refrigerant Europe chooses touse, or even if it chooses to use morethan one (the cost of CO2 is a prob-lem for economy cars, and Europemakes a lot of those). However, whatyou care about is what happenshere. We’d guess that even if CO2

makes the grade, European vehicles

exported to the U.S. (primarily premi-um models) might get R-134a systemsinstalled here, or at least chargedwith refrigerant here. BMW, Mer-cedes-Benz and Audi may commandpremium prices that would allow CO2

a/c systems, but the absence of CO2

system service outside of dealershipswould be a problem.

•If a low-cost DuPont, Honeywell orother alternative refrigerant is cho-sen, it still is unlikely to be used oncars sold here for many years. Environ-mentalists might push for it, but sup-plies would figure to be tight foryears because the market would beuncertain beyond Europe. If a new re-frigerant is a success in Europe, agradual phase-in worldwide mightfollow. What we heard about thesealternatives indicates that they’d forcea learning curve similar to our 1990schangeover from R-12 to R-134a.

Right now you have to deal withan increasing number of complexitiesregarding the R-134a systems youthought you knew well.

EUROPEAN PHASE-OUT OF R-134A

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tied to its anti-global-warming campaign. So you must re-move about 95% of the refrigerant to help avoid overcharg-ing. If you just “short cut” with a single pull of the recoverymachine and leave in a lot of refrigerant, you could over-charge significantly, even if the correct amount of refrigerantis put back into the system.

•Accurate charging with today’s equipment is problemati-cal. As we said last year, the most accurate way to charge iswith an accurate scale, following the equipment manufactur-er’s exact procedure. Although calibrated weights are ideal forchecking scale accuracy, you can come close with new coins.Last year we suggested that 90 nickels plus two dimes addedto the scale should increase weight by one pound. This yearwe’ll also propose a total of 144 pennies to do the job. We re-peat our annual warning: You won’t get accurate results usinga charging cylinder or sight glass, or charging according topressure gauge readings or with small cans.

•Maintain the equipment, which includes changing thecompressor oil (unless it’s an oilless compressor, of course) andinstalling a new filter according to the recommended interval.And treat the equipment carefully. If it’s been knockedaround, it will give the poor results that lead to incorrectcharging, poor cooling and shorter a/c compressor life.

37April 2006

Visit www.motor.com to download a free copy of this article.

The SAE work group on recovery/recycle/recharge equip-ment tested many vehicles and different machines (such asthis ACR 2000) to determine the specifications for a newstandard on refrigerant recovery and accurate recharging.

Circle #23

Recovery & RechargingThe issue of refrigerant recovery and accurate recharging,raised because of today’s small-charge systems with their crit-ical refrigerant levels, has led an SAE work group to draft anew standard for the equipment. As we pointed out last year,vehicle manufacturers specify charge accuracy in today’ssmall systems to under 1 oz. This compares with margins of 3oz. in late-1990s systems, up to 6 to 8 oz. or more in oldersystems. A related problem we also cited last year was thatno one knew how much refrigerant is removed from the sys-tem by the recovery/recycle equipment. These factors ex-plain why inaccurate charging is becoming a major cause ofpoor cooling performance.

Since last year, the SAE work group has had research donethat revealed that even very good equipment may not get outenough of the refrigerant. This is less of an issue when a sys-tem has leaked badly. However, more and more underhoodand underdash repair jobs require recovery of the refrigerantso a/c components can be moved out of the way. In these cas-es, there may be a full charge in the system.

Until new equipment is available (and the EPA is planningto eventually require use of only those machines that meet thenext-generation standard), you can get better results withthese steps:

•Don’t try to recover refrigerant in low ambient tempera-tures. Tests run in the last year (with state-of-the-art equip-ment) indicate that only about 67% of refrigerant may bepulled out at 50°F with a single recovery procedure. At 70°F,the same machine would pull 84% with a single recovery. Ifthe engine is warmed up and the accumulator heated, the re-covery with two “pulls” may go up to over 93%. Moral: Warmup the engine, bring the car into the shop or wait for ambienttemperatures to rise. And allow enough time for at least twopulls (preferably three), with a 15-minute wait in between.

•If you don’t get out most of the refrigerant with the re-covery machine, it will have to be vented with the vacuumpump (even then, only if you run it long enough)—and that’scounter to the EPA’s campaign for refrigerant conservation