What's with these leaky A/C compressors?

[stephenspann27]

My '87 XJ with 270K on it and was needed a can of refrigerant about once very two months.

When I got the jeep (2 years ago) the A/C didn't work. I simply pulled vacuum, charged the sytem with 134A and PAG oil and its been working. I saw and old oil trail down the side of the copressor, and soon as I started running my A/C every day it started leaking oil again where that oil trial was, you can see it bubbling out, its probably a mix of oil and refrigerant.

I knew that had to be the source of my leak, and I planned on replacing the compressor. I finally got around to pulling the compressor off my '89 XJ parts jeep. When I was removing on of the lines from the compressor the threaded part of the housing the line screws onto broke off (The housing broke on the "good" parts jeep compressor) So.. I ended up taking the back section (the housing that has the fitting on it) off my original '87 XJ's compressor, and putting on the '89 parts jeep compressor. I did reuse the paper gasket.. but it was in perfect shape..


Anyways.. to the point: The compressor off the '89 parts jeep that I've been running for 1 day is leaking in the same damn place as the orignal '87 compressor. I saw some oil film there before I installed it but I was trying to be optimistic.

The leak is at the paper gasket between the front plate, and the main housing. I'm thinking about trying to take it apart and replace that paper gasket. I've never taken a compressor apart from the front before.. I did take the back housing off but there was nothing complicated about it. I know there are compressor manuals floating around....

Has anyone else battled this same leak, or taken their compressor apart?

 

[Saudade]

It's always an issue reusing old gaskets. Are they the same model # compressors?

You can find the manual at the Sanden site. I took mine apart but it was trashed. I just wanted to see what it looked like inside.

 

[Saudade]

In case you wanted to see it too.

 

[stephenspann27]

The gasket I reused is not leaking.. its a perfectly machine surface... so.. even though its not preferred you can get away with reusing a gasket ( I didn't want to have to wait on a gasket to be shipped and my jeep to be down).. .. The compressor is leaking at the front where the clutch is.. which I did no touch.. Both compressors leak in the same place..

 

[Saudade]

. Both compressors leak in the same place..

Odd. However, R-134a is "smaller" in molecular size and can more easily leak than R-12. That's why you always read about using "barrier" hoses. Possibly it's the nature of the tolerances in an R-12 system.

I don't see gaskets for these floating around much. Wish I could be more help.

 

[stephenspann27]

if I can't find a gasket.. maybe i can use an ultra thin layer of RTV.. that's what I used on the back portion of the case..

 

[stephenspann27]

I know this pic isn't of the exact same model but its close.. I have arrows pointed to the areas that leak, and have an X on the joint between the back housing and the main housing where I re-used a gasket.

 

[stephenspann27]

Found some info on this site about gaskets and such. The gasket on the back of the compressor is called the "head gasket" http://www.grungle.com/endlessair.html

 

[stephenspann27]

Quote from the sanden manual:

Although oil seepage does not necessarily indicate leakage of refrigerant, it should be
considered a sign that a leak may exist. Look for the following items:
• Oil seepage in shaft seal area (between clutch and compressor) - repairable.
• Pinching or extrusion of front housing O-ring – non-repairable.
• Oil around cylinder head (gaskets, service valves, fittings) - repairable.
• Oil around oil plug - repairable.
• Stripped threads – non-repairable.
• Oil around crack in compressor body – non-repairable.
____________________________________________________________



Because I can see oil bubbling out rather than just leaking.. I'm pretty sure I'm loosing refrigerant.

Looking at the cut away of the compressor design it looks like the head gasket is the only place that should be under pressure. The "front housing" or "Front plate" probably just turns and oil and doesn't have any direct refrigerant pressure because it is below the pistons. Its more like a "oil pan gasket."

 

[stephenspann27]

 

[stephenspann27]

.....

 

[Saudade]

I think the main chamber would have close to the low side pressure when running. You can see the high and low side chambers in the cap on the exploded picture in the link you posted. That's what I saw when I took mine apart.

You can see the O-Ring in the cutaway right behind the clutch.

 

[stephenspann27]

yea I was pretty sure its an O'ring.. I've found some gasket sets, and front seal kits but I haven't seen any O'rings yet.. I I'm 99% sure it only leaks when the compressor is running.. I think I'm going to just leave it alone and see how long I can go before it get low on refrigerant. I have a meat thermo in the vent.. its blowing 40 deg right now.