Old 06-05-2024, 08:35 PM
Tom Pugh Tom Pugh is offline
Junior Member
Join Date: Jan 2024
Posts: 27
Default Adding R12 oil to rebuilt system

I have a newly rebuilt A6 ac system (engine compartment side) in my '67 GTO. I have 60 oz. of R12 and a case (24 cans) of oil which are labeled ' 2oz R12/2oz oil '. (maybe these are just for topping off a system?) Anyway, Not sure how much oil the system takes. Can I punch these cans and add it directly in to the compressor or is there a better way to add the R12/oil mix?

Old 06-05-2024, 11:32 PM
TacoTownCharlie TacoTownCharlie is offline
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Join Date: Jun 2016
Location: Phoenix, AZ, U.S.A.
Posts: 22

I'm working on my R12 system right now so I might be able to help. The amount of oil to add can be a mystery; you have to estimate how much oil is already in the system. Is everything new, condenser, compressor, evaporator and receiver/dryer? If those weren't replaced and were in good working condition (no leaks) then they will have some oil still in them.

If everything is new then you need to check the compressor, it's not uncommon for new or rebuilt units to ship with 8oz of oil in it. If it has oil you need to make sure it is compatible with R12 (PEG or Mineral oil but not PAG oil). I had to drain my new compressor of the PAG oil it shipped with and refilled with Mineral oil.

For my 1978 Trans AM the total oil for an R12 system is 10oz. It looks like 3oz is in the Evaporator, 1oz is in the Condenser and the rest is in the compressor sump. The receiver/dryer usually holds onto 1oz.

Hopefully, someone will have the 67 GTO specs.

Is your system sealed? Is it under vacuum or is it pressurized? If it is sealed but no pressure (no R12 in the system) then you can detach the hoses to the compressor and fill the system from the drain valve. This valve on the A6 is in the middle of the body and clocked to the bottom when mounted.

If it is a pressurized system you'll need to recover the R12 that's in there before you can open the system.

Hope this helps get you started. I'm sure other people will have suggestions and questions. This R12 setup was used for decades and serviced by thousands of people. With a little help I'm sure you will have a a great system.



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