Hi Forum, I've noticed a lot of A/C posts in here lately, so here's another!

I recently put in a new A/C compressor (rebuilt, from air parts), accumulator, VOV, and all new O-rings in my 1995 960. I then brought it into a shop where they evacuated and recharged the system. It worked ok (not exactly freezing) for about 2 weeks, but then the compressor stopped engaging yesterday. I waited a little while and turned the car back on, and the compressor reengaged, but is now making a sqeualing / squeaking noise which can't be good.

The compressor came with explicit instructions to not add any oil because it was already done at the factory, so I don't think that's the problem. Is it possible that the mechanic didn't put the right amount of PAG oil and refrigerant in? When it first shut off, I checked the pressure on the cap and it was ~70psi. The condenser is the same one that came with the car; is it possible that reduced flow from a clogged up condenser caused the problem? Is the compressor done for at this point or is it salvageable?

Thanks in advance!

Kip

If you decide the squealing is from the bearing and not some other source, you may be interested in this piece of trivia: FWIW, I was able to match and replace just the bearing on the A/C compressor for my '94 960 for a total cost of under $20.

There is a thread with more info, including the bearing part number, at http://www.brickboard.com/RWD/index.htm?id=1145029&show_all=1

By the way, the symptoms of my bearing was more of a roar / growl than a squeal (my description sounds like a barnyard fight, doesn't it?)

Hey guys, thanks for all of your responses. I called Air Parts to ask about a warranty on the compressor, and he said that the squealing sounded like a tensioner problem and recommended I try some belt dressing on the serpentine belt to see if the sound goes away. Anyway, it sounds like they'll probably exchange the compressor if this doesn't fix it, so that way I won't have to worry about replacing any bearings. Thanks again for your help.

Kip

An inexpensive mechanic's stetheoscope or a couple of feet of fuel hose strategically placed will tell you whether the noise is from the compressor or another pulley.

DEWFPO
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1998 S90 077,400 and 1995 964 154,100

A squealing sound from the A/C compressor on our 95 960 turned out to be a bad compressor clutch bearing. The clutch itself can be replaced. I have not personally done this but others on this board have.

A small amount of PAG should have been added to the accumulayor if that was indeed replaced. I can't remember the exact amount recommended. Did you drain the old accumulaor and measure the oil removed?

At 72F with a cold (ambient) engine, the static (engine/compressor off) pressure in your R134a should be ~74psi.

With the compressor running, the tube immediately aft of the the VOV should be cold enough to form frost.

DEWFPO
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1998 S90 077,400 and 1995 964 154,100

Can you be certain the oil included with the rebuilt compressor is compatible? I'm a 240 guy, so most everything I know is on the borderline of the R134a revolution, and as I understand it, new compressors are shipped with mineral oil, which must be changed when installing them into "modern" systems. But maybe things have changed.
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-K (hope springs eternal)

Off hand, are you sure the sound is internal to the compressor and not the compressor belt or compressor clutch?
From my limites experience, a compressor that is internally damaged will either make one heck of a racket or will make a high pitched whine if there is not enough lubrication.

On essence I donlt see how the shop that recharged can decide to add oil to your system, without actually knowing that it needs oil . I would think they wouldn't add any.

You might want to check out the place you bought the compressor from to see if there is some kind of warranty.

Greg Mustang
Montreal - Canada

>Off hand, are you sure the sound is internal to the compressor and not the >compressor belt or compressor clutch?
I'm not sure. It only makes the sound when the compressor is engaged.

>From my limites experience, a compressor that is internally damaged will either >make one heck of a racket or will make a high pitched whine if there is not >enough lubrication.
It's a squealing/squeaking noise; maybe it's the compressor belt then?

>On essence I donlt see how the shop that recharged can decide to add oil to your >system, without actually knowing that it needs oil . I would think they wouldn't >add any.
I meant PAG oil added to the refrigerant - I believe with my system there should be 32oz of refrigerant and 2oz of PAG oil.

Unfortunately I purchased the compressor about a year ago but didn't actually install it until this summer, and they only had a six month warranty. I'll still look into it though, but I'd like to try to diagnose this so it doesn't happen again! I think my main question is whether a semi-clogged condenser (which I'll replace) or not enough PAG oil in the system would cause a compressor to fail in two weeks. Thanks!

Kip