Ozone-friendly Air conditioning

[JohnMcIntyre]

My truck aircon is based upon the standard R12 refrigerant and over here in Europe, the vehicle maufacturers stopped making aircon systems with R12 and changed over to R134, which is more ozone-friendly with vastly reduced CFCs.



As I understand it, the two systems R12 and R134 are totally incompatible with one another and if I was unfortunate enought o get a a leak or a failure on my aircon system, it could be extremely hard (read impossible) to find top-up R12 refrigerant.



R. 134 is what is now fitted to all new vehicles in Europe as standard and I weas wondering if Dodge had made the switchover yet, or even if it's on their list of things to do and when?



Given that my own aircon system is just 2 years old, is there any hybrid refrigerent gas which is R12/R134 friendly? Or would I have to consider a complete swapout if something went really wrong with my R12 system?

 

[Mick2500]

John,

I think you'll find that the 2001's are all

134 and not r-12. I'm not certain but I

think the cutover was about 1995 or so.

You should be able to purchase a 134 recharge

kit in an Auto store.



Mick

Tucson

 

[maint.man]

The change over isn't a real big deal. The big thing is to change the seals on the lines with R-134a compatable ones. When I converted my 87' chevy , I replaced the dryer , O-rings/gaskets , the oil in the compressor , and the fittings have to have a retro -fit

fitting put on them to be able to be charged with the R-134a. I then put the system in a vaccuum (sucked all the air out with a vac. pump) and charged it. It's been fine for 2 years and thats a good thing . you'll find that the R-134a is like R-12 used to be,you can get it just about anywhere , and it's only about $4. 50 a lb. (at least in the U. S. ) One other thought , I ended up with about $175. 00 in the swap, and did the work myself.

 

[Marco]

R-134

John,

The AC system HAS R-134 in it!

Any way, if you need R-12, I still have some Kg's here.

Just ask... .



Marco

 

[CumminsPower98]

At work we have many older R-12 systems and I have been putting in Freeze 12, which replaces R-12 and can be bought by anyone. It is cheaper then R-12 also. I have been buying it from Napa and Carquest. The best way to go of course is to convert over to R-134a but that's just more expensive and harder to do.

 

[nickleinonen]

if it is the 2001 you are talking about, you probably already have the r134a.



just as a note to the envrio-friendly people here. while r12 is bad for the enviroment, halon [like in fire extungishers] is the worst stuff avalable. . r11 and r12 are rated at 1. 0 for their ODP [ozone depletion potential], r-134a is rated 0. 0, halon 1211 is rated at 3. 0 and halon 2402 is rated at 6. 0. that's what they like to use in onboard fire suspression systems in race cars. i think co2 or nitrogen or argon would work as well [displaces o2] but halon is still king of the hill. .





this is all the junk i need to know to keep my licence for purchasing refrigerant. . not even a licenced mecanic yet so i can't work on it, but i can buy it.

 

[CJ Johansson]

It's really the oil...

When converting refrigerants from R12 to R134, there are many things which have to be changed to get the system to work "right". There are a few things which *MUST* be changed to make it work for more than a year or two (or even less).



The big thing is the oil. R12 systems use mineral oil. R12 and mineral oil mix very well so the oil gets moved around the system and keeps the compressor lubricated. R134a and mineral oil do not mix, so, the oil does not get moved, the compressor does not get lubricated, and dies an early death. So, the oil *MUST* be changed to one of the PAG or POE oils.



Now, that's not as easy as it would seem. Yeah, it's easy to blow the old oil out and add new. The problem comes from the oil itself. The new oils which work with R134a are *VERY* sensitive to things like water and chlorine. They break down in the presence of these materials and can cause compressor failure. So, blowing out your old oil should be done with dry nitrogen, not an air compressor.



The chlorine part is the tough one. R12 is a chlorinated hydrocarbon. It has chlorine in it. Aluminum parts in your AC system will have some Aluminum Chloride on them, this chlorine can be released and kill your oil over time. So, it's a good idea to change the oil again after a year just to make sure.



Other stuff which should be changed are the receiver/dryer, and if you really want your system to work closer to how it did when you had R12, the condensor and evaporator due to the different temp/pressure curves of R134a (it requires larger condensor and evaporator areas since it's less "efficient" than R12).



All in all, the R12 replacements (Autofrost, Hotshot, Freeze12, etc. ) seem like a better way to go than conversion to R134a. They each have their own problems, some move oil better than others, some have smaller molecules, so require barrier hoses to prevent leaking, etc. But, most will probably work better than R134a since they try to match the curves for R12 and don't require messing with that sensitive oil you need for R134a. One of my favorites can be bought commercially as HC-12a, OZ12 or Envirosafe, but is really just a mixture of 60% R290 and 40% R600a. These can be purchased very cheaply as Propane and Isobutane. Check your local laws though, some states don't allow "flammable" refrigerants, but we could go on for a long time on that subject. For instance, under certain circumstances, R134a is more flammable than Propane, and *LOTS* nastier to your health if thermal decomposition occurs...



-cj



Edit: Oops, for some reason I typed R142 for Isobutane, R142 is an HCFC refrigerant often used in the various R12 replacements. Isobutane is R600a.

 

[JohnMcIntyre]

Once again, you guys come though...

When all is said and done, this thread is a classic example of why the TDR represents an invaluable stockpile of real-world information and hands-on experience. Thanks for all the quality feedback guys;



Marco - I'll pass on the R12 'hit' - are you saving it up for some extra 'kick' in the mad ECM perhaps? I must remember to pack extra sunblock when I'm in your part of the world... .



JMc

 

[M Barnett]

CJ Johansson: It appears you know your air conditioning and may have helped me more than you can know! Heres my story. Bought a new Freightliner in 99 and last year the air conditioning went out. An A/C shop replaced the compressor and clutch. Before we went 100 miles the clutch was burnt up. We put on a total of three clutches in quick order and even a new compressor. shortly after this winter come around and didn't use the a/c. Then this summer the compressor locked up again and last Friday went to another mechanic and I noticed he poured the oil out of the new compressor before he mounted it and refilled it with the PAG oil. The A/C is working but wont pull down to lower than 70 degrees with the vehicle stopped and 55 degres running down the road. Even this warm air feels great when rolling into Phoenix when its 110! Please help me out with this as I've gone crazy trying to figure out what is going on. What you say makes sense to me now and this must be my problem that the compressors come with the wrong oil and some places don't change it out. what should I do now with my system to get it straightened out? Like I said, the mechanic didn't flush the mineral oil out, just dumped it. Thought I would ask you here so somebody else can learn and avoid the greif and expense I have gone through.

Thanks for any help.

Michael

 

[CJ Johansson]

Michael,

If your Freightliner is a '99, it came with R134a and a compatible oil, not mineral oil. All automotive A/C switched over to R134a in '92.



Now it is possible that a replacement compressor could come with mineral oil in it, in which case it would be appropriate to dump the oil out and refill it with PAG oil. Residual amounts of mineral oil wouldn't hurt anything.



Of course, if someone simply stuck a new compressor in which had mineral oil in it, the R134a wouldn't circulate the oil and the compressor would fail.



If it's truely a case of compressors locking up, it's most likely due to lack of lubrication or some other contaminate in the system (dirt, metal filings from the last shredded compressor, etc. ). A good A/C shop should be able to completely flush the system with a solvent, blow out the solvent with dry nitrogen, evacuate and recharge.



As for not cooling enough, the usual culprits are:

Low refrigerant charge - A/C shop can check this with a set of guages

Plugged condensor - clean out the radiator-like thing in ffront of your radiator

Bad fan clutch - it would probably work at highway speed, but not when going slow

Bad refrigerant control valve - this is an internal part that controls the flow of refrigerant into the evaporator. They used to all use "expansion valves", but there are some newer types. A good A/C shop can test this and fix or replace it.



So, I'd find a shop that specializes in A/C rather than the mechanics at a general repair place. Not that they couldn't have a good A/C tech there, but often they have a few guys who know the basics. An A/C specialty shop will have people who are real experts and can diagnose the tough problems.



I know what you mean about the heat. We've been getting into the 90's lately. I've got to get my A/C recharged in the Dodge (I blew a hole in one of the aluminum lines from the compressor when I managed to get an oil filter wrench between it and the 12 volt stud on the back of the alternator ).



-cj

 

[M Barnett]

Hey, thanks for the good info cj, I sure do appreciate it. Yesterday while in Phoenix I went to freightliner and bought a new dryer. None of the shops had one as freightliner come up with some oddball fittings. I also bought a new expansion valve also. My concern was wondering if the first shop didn't put on a compressor with mineral oil in it and I knew the truck come with the 134. The shop last week poured the oil out and replaced it with the POE. Anyway, I think we will get it figured out!

Thanks again

Michael

 

[jsimpson]

I changed my 89 RAM and my 78 Vette over to R134 with nothing but a vacuum down, an oil charge, R134 fitting convertors, and R-134 charge. Four years on the Vette and three on the RAM with icy air and no problems. The 94 was a bit of a different story and I REALLY wish I had flushed it. The evaporator was already leaky (my AC shop stocks RAM evaporators by the hundreds!), so i replaced it. The air is icy now with a 134 recharge, but it had been run for a year on a 134 conversion WITHOUT changing the drier because the drier just wouldn't come loose without possibly destroying the evaporator. Now that there is a new drier and new evaporator, I will probably replace the drier again in a year just to further purify the system. Is there any sure-fire way to tell if you have enough oil aboard your system?