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Discussion Starter #1
I replaced the A/C compressor in my 1994 Deville a couple of years ago. Recently I replaced a water pump that had been leaking. I believe that all of the anti-freeze and water that was sprayed into the engine compartment may have built up a film on the A/C clutch and clutch plate so that it engages but slips.

The A/C "works" in that it gets cold, but it only does so when the RPM's of the engine are up. As soon as the RPM's fall the air from the vents goes humid/warmer and eventually has no cooling at all.

I put a guage on the low pressure port without the clutch engaged and the engine running the pressure was ~140psig. With the clutch engaged the pressure was not much different, maybe about 135psig. However, the air that came out of the vents inside was cooled when I rev'd the engine. In fact, when driving on the freeway, condensate forms on the passenger side window by the A/C vent due to the coldness of the air coming from the vent. Due to this, I believe that the compressor is still working just fine.

What would be an acceptable clutch and clutch plate cleaner? I do not want to mess up the lubrication in the clutch or compressor bearings etc. Before I look at more serious repairs, I believe that a good cleaning of these contact surfaces is in order.

I was thinking that brake cleaner might work. Is there a way to spray soapy water between the clutch and plate? Maybe a mechanical cleaning of the surfaces would be better...

I'm open to ideas or other thoughts.

PS Sorry about the "book" long post.
 

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94 ETC,97 STS
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The clutch may be worn out. Just like a drive line clutch wears out. I've had that happen.

Brake cleaner should be fine. It's made for brake linings which are similar to clutches.
 

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White Diamond '03 DHS (with DTS floor shift)
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I vote for the brake cleaner as well. That said, your problem sounds more like low refrigerant or a condenser clogged with dead bugs aside from the high low side pressures. Was the compressor an A/C Delco or afternmarket? Was it new or rebuilt? Maybe it is failing and the orifice tube is getting clogged with compressor debris.
 

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Discussion Starter #5
When I recharged the system with refrigerant the pressure was around 140psig. So I do not believe that the system is low on refrigerant.

The new A/C unit was an aftermarket NEW compressor. I would hope that I would get more that 18-24months. However, if the clutch isn't slipping, it may be the belt slipping...

Thanks for the help! I'll give the brake cleaner a try.
 

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White Diamond '03 DHS (with DTS floor shift)
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140 PSI is WAY to high for the low side when running. It's rather high even for a static pressure. If it is the belt, your alternator, P/S pump and water pump should also be slipping.
 

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97 Cadillac deville
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Okay so if the clutch was slipping you would see smoke? White smoke how much smoke? Does this apply to a 97 caddy deville compressor also? I do have a bad noise coming from that area when the heat or ac is on. I think its my clutch. But the a/c works fine. Pretty good and cool.
 
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