MarkV Posted June 30, 2011 Share Posted June 30, 2011 Ok I have 2 questions surrounding two different cars and their ac systems! First, I had the 78 Mark V converted to 134-a 5 years ago, the ac is not as cold as before and I want to refill it, with one of those small bottles you can buy at the store, how do they work? do they work well? Second, on the 1988 Corsica, it has not been put over to 134-a (to the best of my knowledge) and I was wondering about those transfer kits you can buy at the store, are they any good? are they easy to use? I do not want to spend 300-500 dollars to transfer it if possible. Just wanted to get your thoughts! Link to comment Share on other sites More sharing options...
Guest Dick Whittington Posted July 1, 2011 Share Posted July 1, 2011 Air conditioning service is best left to the professionals. R 134a is very sensitive to either over or undercharging. Changing a system over is not as simple as some of the kit makers want to make you believe. The system (by law) has to be evacuated and the refrigerant recovered. Dumping R-12, or any other refrigerant, to the atmosphere is illegal. The drier has to be changed, the oil in the compressor should be changed to one compatible with the R-134a. The system will have pumped down with a vacuum pump to remove any moisture left, and then recharged. Link to comment Share on other sites More sharing options...
rhb1999 Posted July 9, 2011 Share Posted July 9, 2011 Dick Whittington is right. If I remember correctly, by law a car retro-fitted from R-12 to R-134a should only be charged to 80% of the R-12 systems capacity. The problem is the oils are not compatible, and mixing the two can damage the compressor. I understand that putting an electric auxillary fan in the rear of the condensor could possibly help with the cooling. As Dick said, the drier should always be changed if the system is opened, this will affect cooling and barrier hoses (with new R-134a approved O-rings dipped in PAG oil) should be used on a retro-fit to help withstand the higher head pressure you get with R-134a. If an R-12 system is to be retrofitted and if the original system has no leaks, (leaks can be detected by putting in a little refrigerant and checking with a electronic leak sniffer, BUT if there is any left in the system after, it has to recovered before the system is opened up.) the mineral oil should drained from the compressor (don't flush a compressor) condensor and the evaporator should be flushed (they make a flush for this) involving compressed air. There are specs on the oil capacity of each system and should be adjusted to the 80%. Of course, R-12 is the best, BUT I haven't checked on availability/pricing of it lately and you have to be licenced to purchase it. I've even heard of people charging R-134a systems with R-12. Hope this helps. Link to comment Share on other sites More sharing options...
Guest Kingoftheroad Posted July 9, 2011 Share Posted July 9, 2011 For all the reasons mentioned above, I let a licensed pro retrofit my classics AC system with the newer R-134a. Had him replace everything he could with new parts, then he charged the system. Link to comment Share on other sites More sharing options...
rhb1999 Posted July 9, 2011 Share Posted July 9, 2011 You're right. Everything should be replaced. But he did say that he only wanted to spend $300 to $500. I guess I read in to that too much, sorry. A question: is your car COLD? If so, that is good. It means that an R-12, OEM system can be retro-fitted with R-134A and still blow COLD. People have told me that some GM cars have warmer air. This should clear things up for me. Link to comment Share on other sites More sharing options...
Guest Kingoftheroad Posted July 9, 2011 Share Posted July 9, 2011 You're right. Everything should be replaced. But he did say that he only wanted to spend $300 to $500. I guess I read in to that too much, sorry. A question: is your car COLD? If so, that is good. It means that an R-12, OEM system can be retro-fitted with R-134A and still blow COLD. People have told me that some GM cars have warmer air. This should clear things up for me.Its cool. I wasn't suggesting he should do anything, I was just saying what I did. Yes, it cold ! Ok, maybe I sent a subliminal message to have it done professionally. lol. The final out come might turn out a better, long lasting result that he won't have keep monkeying with. Link to comment Share on other sites More sharing options...
rhb1999 Posted July 11, 2011 Share Posted July 11, 2011 Thanks. Link to comment Share on other sites More sharing options...
Larry Schramm Posted July 13, 2011 Share Posted July 13, 2011 What needs changing depends on the manufacturer, car, year, when going from refrigerant R-12 (freon) to R-134A. Some vehicles will require everything except maybe the condenser and evaporator core which would include the rubber hoses if they are not barrier hoses. Some compressors are OK with R-134A while others will immediately crater. The best answer on retrofitting a vehicle is to research with the manufacturer of the vehicle / ac system and then go to a person that is KNOWLEDGABLE and proficient with a/c work with the correct tools. Link to comment Share on other sites More sharing options...
PONTIAC1953 Posted July 16, 2011 Share Posted July 16, 2011 hi rhb1999, freon R-12 or R-134a or any other number, are not oils, they are gases, charles coker, 1953 pontiac tech advisor. Link to comment Share on other sites More sharing options...
old car fan Posted July 16, 2011 Share Posted July 16, 2011 I think by 88,R12 was gone.in all cars? Link to comment Share on other sites More sharing options...
PONTIAC1953 Posted July 16, 2011 Share Posted July 16, 2011 hi old car fan, R-12 gone in all cars ?, you must be talking about new cars. nothing that has tried to replace R-12, comes anywhere near being as good as R-12. charles coker, 1953 pontiac tech advisor. Link to comment Share on other sites More sharing options...
Larry Schramm Posted July 16, 2011 Share Posted July 16, 2011 R-12 was being phased out and by 1994 it was gone. Here is a link to the EPA document on the change over.CFC-12 Production Ban Link to comment Share on other sites More sharing options...
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