AC Recharge Suggestions

[Philossifer]

Originally Posted by jalangst

I've been reading some of the other AC recharge threads and I still have some questions. My 89 mustang still has its original compressor but must have a small leak. I have to recharge it once a year. It's low again and I need to recharge it. I haven't converted it to the R-134A and don't really want to at the moment. If there is a leak I fear that this will only make it worse since it runs higher pressure. What is this Autofrost I've been reading about? Can I just add that in the place of the R12 and be good to go. What do yall suggest in my situtation?

jalangst,
If you have a leak, it needs to be fixed. The leak is only going to get worse.

As for some of the other refrigerants like Autofrost and Hotshot. I'd stay away from them. Hotshot is a blend of mostly R-134a so why not just use R-134a instead and Autofrost is blended with hydrocarbon which is basically propane. Not sure it's such a good idea to be charging a car A/C system with propane. I wouldn't do it!

The main problem with these blends is if they leak, you can't top them off like R-12 or R-134a. The components of the blends leak at different rates so if you do lose some, the only way to correct the charge is to recover what’s left in the system and recharge into an empty system. Also, the blends must be charged in their liquid state. And; if you accidentally overcharge, there's no way to remove part of the charge because again, in it's vapor state, these blends separate.

Also, if you ever buy a new compressor, most compressor manufacturers will not warranty their product that's been run on Autofrost or Hotshot! And on top of that, there aren't many shops that will touch a system that's been converted to one of these blends. It's bad enough the law requires them to have R-12 and R-134a recovery equipment, now they'd need to have separate recovery systems to deal with HotShot and AutoFrost.

IMO, you're best option is to fix the leaks, flush the A/C system, add ester oil and recharge it with R-134a and forget the blends!
Phil