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[ted von Kampen]

I know the amount of oil the compressor and system holds for R12. However, is this the same amount for the same system converted to R134a?
I know the oil type is supposed to be PAG for R134a but I am curious about the amount. In one of the posts on this forum it seems to me that someone stated to use only 80% of the oil for the R12 system. Help appreciated

[PaulD_944S2]

I know the amount of oil the compressor and system holds for R12. However, is this the same amount for the same system converted to R134a?

YES, with conditions: You should only replace the same amount of oil that you remove from the compressor, drier, and condensor, evaporator.

I know the oil type is supposed to be PAG for R134a but I am curious about the amount.

NO, if the system was R12 you should use POE oil becuase it is compatible with the mineral oil used in an R12 system.

In one of the posts on this forum it seems to me that someone stated to use only 80% of the oil for the R12 system.

NO. You use the same amount of oil the system requires but only 80% of R12 that the system used. For example, if the system used 32 ounces of R12 refrigerant, then you would add (32 x 0.80 = 25.6) 26 ounces of R134a.

Be sure to drain the oil from the compressor and measure the amount to know how much POE you will need to put back in. Also, install a new receiver/drier and add 2-3 ounces of POE oil to it before installing.

[ted von Kampen]

Thanks for the info. Very interesting. In my case the car had sat open (broken fitting) for 17 years. I decided to reseal it so I have pulled the compressor out and tore it apart. I have cleaned it and removed all old gasket, rubber seals etc. I have the new gaskets and rubber and it is ready to reassemble. I flushed the system using one of the commercial AC flushs on the hoses, condenser and evaporator. I may use one more can of flush on the evaporator. when I blew out the evaporator and hoses the flush was pretty clear but after using the whole can, the last few drops removed with the compressed air still had a bit of orange color. There is a lot of volume in the hoses and evaporator.

Considering that I have dissembled the compressor and will be reassembling it in a day or two do you think I should use the POG oil rather than the PSG oil. Your comment on the amount of R134a is noted and can be adjusted when charging.

Of course I have to assemble the system, put in a new recevier/drier and vacuum it out and leak check it before charging.
Your further comments would be appreciated.
Ted

[ted von Kampen]

O noticed on review that I mistyped a word. In the previous reply the phrase
---than the PSG oil.--- should have been --than the PAG oil.
Ted