AC Clutch Squealing

[stewy]

I just installed a Vintage Air Gen IV system in my car with a Sanden compressor and March serpentine belt pulley set-up. I put a vacuum on the AC system for 25 minutes and then put a 12oz bottle of 134 to the low side. When the compressor came on it just began to squeal as it would slip. It would only get worse with higher rpm's. The belt is tight.

Will the compressor slip until it is fully charged? I did have to remove the compressor from the system to pull the motor before I had the chance to charge it when my cam went, so some oil was lost, but only about a tablespoon. Should I just bear with the noise until the charge is higher? I don't want to ruin the compressor, so I just turned the ac off and came here for advice.

[stewy]

Is it possible that a safety switch in the system is turning the clutch on/off since the system (both sides) are low?

[lnirenberg]

I have been having the same problem with my system. It did seem to coming from the compressor but I have a Street & Performance serpentine system (I do not recommend) and they use sh** Chinese bearings in the idler pulleys. I started there by replacing all 4 bearings with American made parts. Still squealed. I changed the serpentine belt which was about 2 years old and on inspection had a lot of cracks. Still squealed. I changed out the compressor charged it back up. Still squealed. I'm at a loss and not happy until my nephew came over to the house. He had the same problem with his Camaro and a mechanic friend of his told him to squeeze a little high temp grease in the small space between the clutch plate at the front of the compressor and the pulley, run it and then repeat a total of 3 times. To say I was skeptical would be the cleaned up version but out of ideas I had nothing to lose. This was on Friday and it hasn't made a peep since. I have never heard of this and if my nephew had come over a week earlier I could have saved $450 for < $.01 of grease. Anybody need a perfectly good Sanden style compressor?

[Mike Holleman]

Is it possible that a safety switch in the system is turning the clutch on/off since the system (both sides) are low?
Dave, Be sure you have a good ground to the comp. If it is a one wire add a ground wire to the body of the comp. Sometimes a lack of a good ground will not hold the clutch tightly engaged and you get a squeal.
Mike

[paul67]

I found the idler pulleys touching on mine ,street and performace.

[stewy]

Dave, Be sure you have a good ground to the comp. If it is a one wire add a ground wire to the body of the comp. Sometimes a lack of a good ground will not hold the clutch tightly engaged and you get a squeal.
Mike

Thanks Mike, I'll give that a shot. I did call up Summit and they said that if I got an ok from March Performance, since I purchased it two years ago, that they would replace it. I tried spinning it by hand w/o the belt and it does seem tight. I took it off the car once before charging, but capped it right away with the supplied cap. I had to pull the motor. Plus the lines were capped off, so I don't see how contaminants could have gotten introduced to the system. Ran a vacuum for over 20 minutes before attempting to charge. Perhaps a significant amount of oil was lost when I disconnected the compressor? I remember loosing some, but did not think it was much.

[Mike Holleman]

Thanks Mike, I'll give that a shot. I did call up Summit and they said that if I got an ok from March Performance, since I purchased it two years ago, that they would replace it. I tried spinning it by hand w/o the belt and it does seem tight. I took it off the car once before charging, but capped it right away with the supplied cap. I had to pull the motor. Plus the lines were capped off, so I don't see how contaminants could have gotten introduced to the system. Ran a vacuum for over 20 minutes before attempting to charge. Perhaps a significant amount of oil was lost when I disconnected the compressor? I remember loosing some, but did not think it was much.
I found this out the hard way. On my Tempest with a March serp. setup, I kept having a squeal and thought belt, but new belts and over tightening did not stop it. March said if I was relying on a ground thru their brackets that may be the problem. I took an alligator clip wire link and went from the engine ground to the comp. housing and the squeal stopped.