Converting AC back to R12???

[dhauser]

If you convert your AC system to 134A (assuming you don't change out your accumulator, drier, or compressor), can you re-evacuate everything and recharge it with R12?

Anyone done this? Results? I'm not really interested in a discussion of the merits of any certain type of refrigerant (we've all BTDT already), but whether this can be done safely or not. Thanks.

 

[GNVAIR]

Yes, you will have no problems what so ever. At a shop I worked at, we mixed R12 and 134a with no problems.
Most of the compatibility issues are a total myth IMHO.
Just remember it will take more R12 to fill the system than 134a.

 

[dhauser]

Thanks Lee. That was the answer I was hoping for. I have never had any luck getting those cheap 134A retro fit kits to cool very well, and just am a believer in using cold R12 in an R12 system.

 

[turbodave231]

If your system was converted to R134A a couple of thing had to happen. Someone added either Ester or PAG oil to the system before the charged it with R-134a.

R134A won't move the mineral oil used for R-12. Without the new oil, a system using R134A will burn up the compressor from lack of lubrication.

Assuming that you still have mineral oil in the system, you could pull a deep vacuum (28-29"Hg) for 15 minutes or so and recharge with R-12. If you don't have mineral oil in the system, you better put some in or prepare to replace the compressor. R-12 won't move Ester or PAG oil.

In either event, I would pull the accumulator and drain the oil out.
That way you can see how much oil is in the system.

Why to you want to convert back anyway? You must have alot of R12 laying around or alot of extra money.

Dave

 

[dhauser]

Thanks for that info Dave.

I have never cared for R134A, although everyone else thinks its great. I had a brand new 94 TA that had 134 and it was never cold, not even when new. I've retrofitted a few cars with 134 and been disappointed. Never cold enough. My understanding (and I know some will disagree) is that to properly run 134A in an R12 designed system, you need to replace components, or you won't get as cold a charge, more leaks, more often, and round it goes. I'd rather pay a little more up front for R12 and have it cold and done with. Just my preference I guess. I have a shop that will sell it to me for $40/lb or so, which is ok with me.

I may still ask them their opinion about leaving the R134A in, but I know they prefer R12, and they are very very good at what they do.

 

[Steve Wood]

134A works great in the newer cars that I have with it. On my Regals, it cools but does not get cold. I just put a new compressor, dryer, and orifice in my son's car which already had 134a in it from an earlier conversion. This time, I tried a variable orifice tube but I cannot tell much difference.

If you has ester oil in there, I don't think you will have much trouble reverting to R12. Most of the conversion kits use ester, I think. If it had PAG in it...then it has to be removed completely,

There is a fair bit of ac information online so you might do a search and get a few facts before you start.

Maybe, if we had a big enuf condensor, it would work better. At one time, Tony D was going to offer one but, I guess, he cannot keep up with his IC business so he never did.

 

[tc86gn]

I have 12 in my GN and I agree if you can put 12 in it..... do it.
Also have a retrofitted system in an 82 chevy pickup but changed everything and it works great. WS6 T/A cools fine with 134A also. It gets REALLY HOT here!! I decided to stay with 12 in the GN because it cools better and we have additional heat around the evaporator core box and drier. IMO