Cannot get compressor to engage

[JohnHere]

Your car is very complex with redundant electronics controlling just about everything, including the A/C. You found a leak for sure at the compressor that needs to be addressed. But that doesn't explain why the compressor won't start as it should while charging the system through the low side.

It could be as simple as too wide a clutch gap, a bad pressure switch, or something obscure like a faulty control head in the dash failing to communicate with the A/C amplifier, which could also be bad, and in turn commanding the compressor to turn on.

I don't recall anymore, but have you checked the clutch gap with a feeler gauge? On most vehicles, it should be about .020". Smaller than that is okay as long as the clutch plates don't drag. Greater than .020" and the clutch might not engage, just as you're experiencing. Try getting a feeler gauge in there to measure the gap. Some people use a business card for that purpose as well.

[Beamer.619]

So I installed the new pipe pulled a vacuum for 2 hours then started to fill the system with refrigerant and I saw the compressor engage for about 5 seconds then turned off so I took the relay out and bypassed it with a wire so the compressor was running right when I started the car so I started filling the system with the rest of the bottle of refrigerant and took most the bottle then the belt started slipping on the compressor and made a loud screeching noise and then the compressor clutch shut off so I turned off the car. I then pulled the wire out and put the relay back in the car and tried the running the compressor it tried turning on but the belt kept slipping for about 3 seconds and then it gave up and just wouldn't engage. What could my issue be so far I haven't see anymore leaks from where it was leaking from.

[bohica2xo]

And the good old jumper wire kills another compressor.

That little wire sells a lot of parts. No you get to guess how much of the compressor metal went down the discharge line as it ground to a stop.

Your compressor is seized from a lack of lubrication return, Running when the system said it should not.

[Beamer.619]

I got a new compressor, expansion valve, and drier the car was retrofitted in 2000 from r-12 with mineral oil to r-134a with ester oil. I'm doing a full system flush and replacing everything except for the condenser and evaporator my question is should I use ester oil since that's what they used when they retrofitted it or should I use pag oil.

[JohnHere]

I advise replacing the condenser as well because that component acts as a filter, too, and it's very difficult if not impossible to flush out any debris that might be lodged in it.
Since you're replacing and/or flushing everything, I would go with PAG oil...PAG-46 specifically.

[JohnHere]

Double End Capped PAG, if you can get it.

[Beamer.619]

my condenser is a old style condenser so it can be flushed easily I plan on using the same condenser. It looks like pag oil is my best option here since Im completely flushing the system out so I will be using pag 46 will report back when system is install and filled with refrigerant.