Page 2 of 3

Re: R12 system on 79 Trans Am

Posted: Sat Mar 21, 2020 5:06 am
by warrenseale
The inlet and outlet lines of the evaporator are cool, not cold as they normally should be. The hot/cold damper door is functioning properly.

Re: R12 system on 79 Trans Am

Posted: Sat Mar 21, 2020 7:09 am
by Tim
Unless I'm missing something. Full Refrigerant, cool inlet and outlet lines, hardly any variation from static pressure. Compressor spinning.

Seems to be a bad compressor.

Re: R12 system on 79 Trans Am

Posted: Sat Mar 21, 2020 8:07 am
by Al9
Agree, definitely sounds like a compressor featuring either seriously worn pistons/cylinder walls or broken reed valves.

Re: R12 system on 79 Trans Am

Posted: Sun Mar 22, 2020 9:38 am
by warrenseale
Well I opened up the system and pulled the orifice tube and found a couple pieces of rubber that looks like o ring material but which is not from the pipes/hoses. More concerning is that the screen was loaded with metal particles. Prior to the rebuild when I pulled the original 40 year old orifice tube, there was no debris plus I flushed and blew out the system prior to installing the compressor. Now I have to deal with the rebuilder :x

Re: R12 system on 79 Trans Am

Posted: Mon Mar 23, 2020 11:04 am
by JohnHere
Offhand, I don't know what the specs are for your car. But if the rebuilt compressor was empty of oil when you received it, did you add the correct amount and type of oil?

Re: R12 system on 79 Trans Am

Posted: Tue Mar 24, 2020 10:59 am
by warrenseale
The rebuilder fills it with 11 oz of ester oil. This is the full oil capacity of the system. Anyway, they are having me ship it back to them.

Re: R12 system on 79 Trans Am

Posted: Wed Mar 25, 2020 6:13 am
by Al9
Which viscosity might be an interesting question. The A6 is pretty sturdy but too thin of a oil and friction becomes a problem.

Re: R12 system on 79 Trans Am

Posted: Fri Mar 27, 2020 12:09 pm
by warrenseale
Well the rebuilder received and inspected the compressor and found an extra o ring inside it. They removed it and said that otherwise the internals look OK. They said the extra o ring would have caused the symptoms I experienced. We'll see! At least they turned it around in one day and paid for shipping to and from. The final testing shows it is working normally. I asked if they tested it the first time when the extra o ring was in place. They said that either they missed that step :o or it checked out OK at the time.

Re: R12 system on 79 Trans Am

Posted: Sat Mar 28, 2020 8:56 am
by JohnHere
I wonder where the metal particles came from, though. Usually, that means something inside the compressor is disintegrating, as mentioned earlier.

Re: R12 system on 79 Trans Am

Posted: Sun Mar 29, 2020 9:24 am
by warrenseale
JohnHere wrote:I wonder where the metal particles came from, though. Usually, that means something inside the compressor is disintegrating, as mentioned earlier.
Most likely from the compressor prior to the rebuild. Some particles could have been sitting in the bottom evaporator tank even after the flush.