Automotive Air Conditioning Information Forum (Archives)

Provided by

We've updated our forums!
Click here to visit the new forum

Archive Home

Search Auto AC Forum Archives

Retrofitting back to R12 System

macs_5 on Fri August 07, 2009 1:40 AM User is offline

Year: 88
Make: Toy
Model: 4x4 PU
Engine Size: 22RE
Refrigerant Type: OEM R12/134 now

Hi, I have had a clutch fail on this truck and have decided to go ahead and replace the compressor and clutch as an assembly. The system was converted to R134 2 years ago and last summer sprang a leak causing a total discharge. This past couple of months, the evaporator was pulled, flushed and new expansion valve and o-rings installed. A new drier was installed, an idle up vacuum switch was replaced. About 3 ozs of PAG was charged into the system to replace oil lost during the repairs made above.

Okay, Questions I have are about returning this system to R12.

I understand that most compressors come dry, so they need to have oil installed. I plan to use whatever Toyota recommends in the service manual for R12 Systems.
How much of a problem is the PAG oil that was installed into the unit when it was converted? (I am guessing that residual would be small amount since compressor is being changed)?
Should I replace the drier again?
Everything else is still R12 factory OEM equipment.

Normal ac service, deep evacuation, recharging with weighed in R12.

Any tips, pointers or other advice for this situation?

Thanks in advance.



TRB on Fri August 07, 2009 9:36 AM User is offlineView users profile

If you want to go back to R12 you need to completely flush the system to remove all traces of PAG oil. Drain your compressor and pump some mineral oil through it a few times before adding back the oil amount needed. Drier would need to be replaced also.


When considering your next auto A/C purchase, please consider the site that supports you:

Back to Automotive Air Conditioning Forum

We've updated our forums!
Click here to visit the new forum

Archive Home

Copyright © 2016 Arizona Mobile Air Inc.