R134a back to R12 w/o proper R134a conversion (1 Viewer)

[jellis]

I replaced my AC compressor and condenser about a year ago in my HDJ80. I took it to my local shop and they filled it with R134a. Silly me, I didn't know it mattered!

Fast forward to a few months ago and my compressor seizes up while driving down the freeway (nasty burning smell from belt, popped to hood to see AC compressor froze up, simply turned off AC to solve the problem). The AC compressor does actually work with my center console ice box but will seize up if I run the full air AC system. I was thinking I needed more oil, but after looking into it I think the problem is more likely the R134a not dissolving the mineral oil and lubricating the system properly.

The simplest fix seems to be putting R12 back in there instead of R134a. The replacement compressor came with mineral oil, and I don't think it was properly converted to R134a (oil, hoses, switches, valves, etc.)--so why wouldn't this work? The system seems to work just fine other than the compressor seizing up.

I've read a lot about R134a conversions wanting to go back to R12, but that's not the case here. It was never converted. Can't I just pull a long vacuum to get any residual R134a out of the system/oil and put in R12 and call it good-enough-done?

 

[leonard_nemoy]

I am no expert but it is my understanding the two are not compatible and cause problems when mixed. This is why to do it right the entire system needs to be converted, and now that you have the r134 In there I think you would need a way to clean out the old system other than just sucking it out.

 

[inkpot]

To get r134 into an R12 system, someone had to mount the adapter fittings to the high and low ports on the compressor. It is really hard to remove them. You will need to flush the entire system regardless of which gas you choose to stay with. In this case, a hybrid is NOT a good thing.

 

[baldilocks]

http://tms.cleanautoalliance.org/documents/ac002t98.pdf

All you should need to do is evacuate the system, install a good compressor,a new receiver/dryer, service with the proper amount of PAG46 oil and r134a per the tsb.