I converted both my '90 and my '92 to what, at that time was called R-12a. I purchased it from, http://autorefrigerants.com/hydrocarbon-refrigerants. They advertise that it is a harmless gas and don't need a license to DIY. I changed the compressor, had to, it was giving problems, flushed the system with their product, added some stop leak and charged the system. It has worked just fine. I do get a "Low charge" reading after a short time of running, but I hit the reset and never see the message again. Due to the different operating pressures, I assume the switches don't register quite the way they should, but the air is cold and I have no complaints. The refrigerant runs at a lot lower pressure than R-12 thus it is easier on the compressor and other parts. All in all, I find it a good product.
In order to change out refrigerant with any degree of long-term success , You must at a minimum replace the accumulator and install a new orifice valve as well as flush out as much of the old mineral oil as possible in the evaporator , condenser and lines . When You pull the old orifice valve , it's condition will give You a good indication of the ac compressor and over-all health of the vehicle a/c system. (depending on what the screens capture)
I recently evac'd and recharged my 92 with R12, I have several cans of the old good stuff. Also check your cooling fan relays, this can cause a A/C malfunction, I will have to replace mine as I found them to be defective and the a/c won't work properly. My 88 beige Eldorado was converted to R134a just before I bought, I doubt they replaced a whole bunch of A/C parts when they did it because I got it from a used car lot. I had to add one can of Freon about a week after I bought it, then another can about a month after I bought it. It gave a low refrigerant code also, this was also 2 years ago and it has worked perfectly since and haven't added any Freon. I find R134a to work adequately in the Eldorado, the 86 Seville I had before was r12 and worked noticeably better. The allante's climate control fan doesn't seem to blow as hard as the Eldorado or Seville of the same vintage, at least compared to the 92 allante that I have now, which is why I choose to keep it r12.
Well I replaced the clutch assembly along with the pulley cause the bearing was bad. I gapped the clutch @ .037 and it engages & disengages but the DIC still tells me low refrigerant. So now I will evacuate the system & recharge. I'm told I can use freeze 12 without any problems & others tell me no. I don't know what to believe anymore.
(NOTE) My Allante has been garaged since 1998 and was only started every now and then to keep everything lubed but it blew the clutch completely off and I'm thinking it was caused by the pulley bearing.
I've heard of freeze 12, but really don't know much about it. If DIC tells you low refrigerant, probably have to add more or evac and recharge. Make sure your cooling fans are consitantly running with a/c on at idle, mine go to full power for 2 seconds then off and cycle, not right, defective relays. If you convert to r134a I've noticed you have to overcharge it a little to keep the low a/c message from coming on.
When dealing with the AC system of the Cadillac Allante, the best practice is to stay with what the GM design team used at the time that the system was designed and was designed for. The boys at GM, who knew best, spent big big dollars designing a system which consisted of many components to work and work perfectly and for the long term. If a change over to an alternative refrigerant is completed, the result will always be lacking. The system was not designed for a "replacement refrigerant, PERIOD.
Without R-12, you will always be chasing the "equal performance level " and will never achieve it. You will notice this the first time you come to sit in 80 + degree whether in slow or stopped traffic. There is no ramp up time for R 12. It is instant cold. On the other hand , with an alternative refrigerant such as 134 a or Freeze 12, good luck.... there is a ramp up wait time..
Regardless of what may be stated R-12 is still very available. The issue is finding a shop that is knowledgeable and can work with it. They are out there. The real mitigating factor is expense. R-12 is more pricey, however, there is an old saying, "the cheap comes out expensive". Short cutting when doing the AC system on the Allante will leave the end user with a system which will not perform at near the level of one configured and charged as originally designed. When compared in the final end game to a system which was properly switched over to 134 a, the 12 still far exceeds in performance.
If the end user is insistent about going with 134 a , and will do the job correctly, the entire system requires flushing and changing of the typical parts, the orifice tube, the accumulator, and the drier. Beyond the typical, the AC pressure lines will need to be replaced. In short order the stock ones will begin to leak out the 134 a as the 134 a molecule is smaller. All hose seals will also need to be replaced. The low and high pressure switches will most likely not function correctly due to the different pressures that 134 a runs at.
After all this you will end up spending probably more than it would have cost you to just remain with R 12 and do a recharge, AND you will have a converted system that does not cool anywhere near as well as what an originally configured and charged one would.
The cash outlay really is not that great when you consider all factors of a properly operating system. Over the long haul, I would want a properly operating system, which performs at a peak level. You simply can not get that with 134 a or any replacement refrigerant such as Freez-on or Feeze 12, no matter how you rationalize it. These are my opinions.
Well I had no choice but to convert cause I couldn't find R-12 anywhere for a descent price and everyone that had it required ac certificate.
But all in all I'm satisfied with the performance of 134a .
How long it will last is another story.
I did change everything but the hoses. After much consulting & checking around, I followed the best advice I got from the most ac techs.
I don't know if it is as cold as R12 cause its been too long ago since I used it .So with that said I really don't know what I'm missing.