Does anyone know the specs for the AC compressor oil charge, I have the R12 charge quantity, just need the oil. Im replacing my compressor and want to have this right without guessing. I'll use 80% or the R12for my 134a charge Thanks 1973 mustang 302 with Factory air.

 

If you need an answer without a guess, then that leaves me out, except that back in the R-12 days they used to call the oil charge an oil charge because that is all there was. I think you will just need to verify this on the oil container.

The guess comes in with Ester oil, which is compatable with R-12 and 134, but I am not sure as to whether it is 100% compatable with your old system, but I think it is.

All of this brings me to a question, why run R-12 anymore when 134a is much more affordable, and conversion is not so hard? I know R-12 does cools a little better, but.....

 

I am using 134a, I just need to know the amount of oil the system required originally as to charge it with oil now, not the refrigerant quantity, but the oil quantity I need. It should be in a service or owners manual, lucky me I have neither Help!

And oh yeah, I am using neither 134a or R12 in another classiccar, im actually using HOT SHOT, its yet another drop in for R12, but its not as popular as134A. I forget its R# though, I use it and the box says HOT SHOT lol Its colder than 134A I feel, butI want to use 134A in my mustang though.

 

I have charged lots of systems with the york style compressors, (old Ford type), and I always use 4 oz. when I know that the system has little or no oil in it, everytime without issue, (except for once, see below) but then you didn't want a guess!!

Using this method, I routinly get 100,000 to 130,000 miles from these compressors. Too much oil is worse than too little oil, I know this as well, learned this the hard way once. It can break a drier internally, this releases hundreds of little pebble sized "BBs" into the system that can haunt the AC system for a long, long, time.... even after changing all of the hoses.... OUCH.... [:@]

 

So I want to just dump that ester type oil right in the compressor? It says in the instructions half in the compressor and half in the suction line charge port. Can you dump that oil that comes in those cans like the refrigerant that you buy at autoparts stores in those metal cans, you know the type you use the hose and screw it on, or do I need to buy ester oil I can pour in. I have done alot of appliance type refrigeration work, where the oil comes in the compressor, but not much on cars, at least no replacing of compressors on cars that is. Thanks for your help

 

I think that the oil that you pour in is better, but I will confess to usually always using the presurized oil, because it is easy...

But when using the pour in type, I just pour it all into the suction side of the compressor, and give the compressor a few turns (with the discharge hose hooked up). Upon reflection though, it is probably best to put some through the crankcase plug as well... but I never have... never had any issues.

 

approx. 4-5 oz of oil, approx. 19 of refrig.and the AC works great now, thanks for all your help

 

I would not pour all of it into the suction. I do commercial A/C for a living you could wipe out the valves. Put half in discharge and half in suction. Polyester oil only if you use 134a. It is only good for about 15 minutes once open to the air because it is a very miscible oil.