Hey guys,
I am confused on waht oil to put in my A/C system after I evacuate the R12 and convert it to R134a. I have heard several mentioned. Ester oil, PAG-42, PAG 100, Mineral oil.

I have heard Ester oil doesn't mix well with R134. PAG 42, I have heard this is the stuff to use. PAG 100, Heard this stuff is too thick for Ford Compessors. Mineral oil, not sure about it.

What is supposed to go in the system with a stock compressor on my truck (see sig) with R134?

Any information would be appreciated.

 

Flush, evaporator and condenser, and drain the compressor. Also if you're retrofitting most people will recommend you use ester oil (HFC-100).


When you replace the accumulator/drier, install the proper amount of new oil in it. When you drain the compressor, measure what came out, and replace with the same quanity. Don't forget to replace the o-rings with new green ones if you haven't, using Nylog to seal them. You should also install a HPCO switch.

 

Ford requires low-viscosity PAG oil (PAG-42) in all its compressors using R-134a. Mineral oil is what R-12 uses. Ester isn't recommended by Ford.

 

but pag oil wont mix with mineral oil in the system. ester oil will.if you changed every part of the ac system or use a flush to remove all of the old mineral oil, go with pag oil. but otherwise use ester oil. thats what i did with my truck.

 

Ford (and most others) also recommend flushing the entire system to clear the old mineral oil.

 

but if you flush the system, the hoses should be changed to barrier type for 134. the flush strips away the coating on the inside of the hoses that should keep the 134 from leaking through them. who wants to spend all that money and time. i would have to change my condensor if i changed all the hoses because the line is frozen at the connection. bottom line is i got my ac working almost good as new for 14 bucks worth of 134, 2 bucks for new o rings, 6 bucks for a bottle of ester oil, 10 for new 134 fittings. total 32 bucks plus tax. sure you can change the desicent hoses ect, but why spend the money?

 

I've never heard of that, and I've read & OCR'ed the MACS manual that discusses it. They always recommend the flush, and they do NOT list barrier hose as a requirement for R-134a. If you want it, send me an e-mail & I'll attach the 5.5M document to my reply. You might be able to view it on BroncoData since I sent it to him a few weeks ago.