Big Dave

This is probably a silly question, but I haven't seen anything on this particular topic yet:

1. What is the proper way to drain oil from the AC compressor?
2. What is the proper way to refill AC compressor with new oil?

Thanks in advance!

AO

1. Dump it out.

2. Fill it up.

When you take off the plate where the hoses connect, you will see the oil down there. I think you just turn it over and it will pour out. Then refill with the proper amount and type of oil.

Big Dave

Which one...green or red? Both? Does it matter?

AO

That's different than mine.... Can I pass?

I'll "'91 GT AC systems" for $100, Alex.

Ispeed

Open both up. Turn the pump slowly when you fill. I know mine takes 9oz of oil for the whole system. My old compressor most likely died from no oil in the system.

doktor-t

Interesting, my compressor leaks oil, not very much but it indeed does leak.

What about the R12, did you just purge it out or were it already gone when you released the hoses?


/Tobias

Big Dave

My R-12 leaked out a long time ago via a blown compressor seal. I'm converting to R-134.

Tampa 928s

Compressor takes 6 Oz rebuild it not that hard while it is out!

David L. Lutz

I am exactly at the same stage you are and just yesterday I drained the oil out.

I just turned the compressor upside down and oil just poured out. Then rotated a bit and more came out. Did that for a while until I think all is out. I don't plan on taking off the plates (unless someone here tells me differently) and I plan on putting about 6 oz. of oil back in thru the "green" port you have marked. (the "green" port is where all the oil pour out from)

I replaced the clutch bearing (it seemed a little rough), but am not planning on a rebuild.

doktor-t

I think the shaftseal is the one that causes the oil to leak out. Are there many seals to change for a overhaul?

Except for the oilleak my compressor is all good.


/Tobias

Big Dave

I'm being lazy...what's the correct type and volume of oil I'll need to refill with to convert my '85 to R-134 (no rear air)?

dr bob

To make sure you get as much of the old out as possible, drain through both ports, turning the compressor shaft right and left a few cycles each. Measure what you take out. Then pour another charge into the compressor, roll it again a few cycles each way, then drain. Do it again if you have enough oil to spare. Then charge with at least as much as you took out, plus the WSM allowances for the drier. If you pull/flush/purge the condenser too (recommended) you'll want to add an ounce or two for that.

Before you install the compressor in the car, turn it so that the clutch is down, and rotate the shaft a few times in each direction to be sure to get a good film on the friction faces of the shaft seal before you evacuate and before gas is introduced.

Once the compressor is installed in the car and all the hoses are connected, rotate the compressor shaft by hand a dozen rotations to make absolutely sure that the oil hasn't pooled in a lower cylinder, risking a slug on initial start.

----

I've settled on the polyolester oil as the best choice for R134a conversions. It's supposed to be a little less hygroscopic than the PAG, and has the added benefit of getting along well with any mineral oil left in the system from the R12 days. I know that many of the 'conversion' packages, like the one with the Castrol name on them, include PAG in the kit. Maybe it's users' choice like motor oil. My basic research was almost 10 years ago, and no worries at all since the conversion with POE in the system. Hard to believe I did that conversion 10 long cold tears ago.

SteveG

As opposed to hot, burning tears. What a poet.

dr bob

OK, could go either way I guess. 10 long cold tears, but ironically, no regrets?


Darn keyboard can't spell....

David L. Lutz

thanks Bob