A/C Assistance

[Bob Chadwick]

Last year I converted my a/c to R134. It blows at about 38 degrees when it is working correctly. I've had a couples of setbacks that were repaired under warranty. The latest was the valve behind the compressor had vibrated loose and had leaked refrigerant.

I was talking to the guy, of course the guy that did the original work is no longer there, and we were talking about the condenser (the thing in front of the radiator in case I got the condenser and evaporator confused). This was replaced last year with a stock replacement of the original size. He suggested to me that R134 works better with a smaller condenser and that the shops automatically replace them with the R12 replacement due to fit considerations. Has anybody heard of this before?

He has also indicated that they use an oil that is compatible with both R134 and R12 and suggested that he would convert it back for the cost of the refrigerant. When this is done he felt that I would get 32 degree air rather than 38. Any comments on this as well, particularly as it relates to the oil.

 

[DDLS3]

Well thats one I have not heard. 134 does not cool quite as well as R-12 thats a fact. R-12 is near obsolecence and at a $100 + per pound, should be. As to the oil question, yes I believe that both refridgerents use compatable compressor oil. I charged my original system on my 81 with 401B after vacuuming off the remainder of the R-12. No condenser, orifice, or oil changes required, 3 years inservice, no problems, nice cold 34-36 degree air. Hopefully someone with more hands on experience than I have will add some to this thread.

 

[clar2001]

The oils are not compatable they have two different kinds of acid in them. 134a is not a drop in replacement althought a lot of people will tell u so, you should always change your filter dryer any seals ans hoses drain the oil from the low point your condiser before converting to 134a .My experence and many others it does not work near as well as R12.but is much cheaper really not worth the $ saved .R12 sells for $40 lb unless u buy quanity then its a little cheaper.

 

[JohnZ]

I was talking to the guy, of course the guy that did the original work is no longer there, and we were talking about the condenser (the thing in front of the radiator in case I got the condenser and evaporator confused). This was replaced last year with a stock replacement of the original size. He suggested to me that R134 works better with a smaller condenser and that the shops automatically replace them with the R12 replacement due to fit considerations. Has anybody heard of this before?

He has also indicated that they use an oil that is compatible with both R134 and R12 and suggested that he would convert it back for the cost of the refrigerant. When this is done he felt that I would get 32 degree air rather than 38. Any comments on this as well, particularly as it relates to the oil.

R134a does NOT work better with a "smaller condenser". R134a is a less capable refrigerant than R-12, and the OEM's went to more efficient condensers (not necessarily physically larger, but more tube-to-fin contact area, and more costly to manufacture) when we made the conversion on newly-designed cars in the early 90's. There is no refrigerant oil that is compatible with both R134a and R-12 and meets any OEM manufacturer's durability requirements.

 

[Tom73]

I use R-416a which is a drop in replacement for R-12.

Len,
Could you define what you mean by "drop in replacement for R-12"?

tom...

 

[Bob Chadwick]

Ester oil is the oil the guy mentioned. I'm getting conflicting info on this and it's compatability with both types of systems. Some people are syaing no oil is compatiable with both and I've read elsewhere that this is.

Thanks everyone.

 

[Bob Chadwick]

Thanks Len. I'll probably give you a call before I go back in two weeks.

 

[Tom73]

drop in as in nothing needs to be changed other then pulling a good vacuum.

Thanks Len, appreciate the definition. A lot of people think that "drop-in" is something that can just be added to the system on top of the existing refregrent. Drop-in is a term that the EPA avoids.

As was mentioned on another thread, R-416A is sold under the name FRICG FR-12 (EPA http://www.epa.gov/Ozone/snap/refrigerants/lists/mvacs.html ) which is a mix of HCFC-124, HFC-134a, and butane. 59% of it is 134a. Since it is 59% 134a, it would seem to me that you would need to also change the oil and the dryer to 134a compatible components.

tom...