noisy a/c when off - clutch?

[mazzov]

My A/C makes a tinnie sound not the sound that you would hear from a bad bearing when it is not turned on. The noise goes away when I turn the A/C on. It has become more frequent but not constant. I had it serviced 2 years ago and it works like a charm. I'm thinking that it could be the clutch on the A/C.

Any suggestions please reply.

96 Lumina 3.1

Thanks, Vince

[Manny_boy]

Not your clutch, more than likely the bearing for the pulley that your serpentine belt rides on is what you're hearing.

[mazzov]

Is the pulley a replaceable part?

[Manny_boy]

Yep, it is. Its expensive if you buy it brand new from the store (somewhere in the area of $100.00 just for the bearing) you'd do better going to a junkyard, and pulling a compressor with a good pulley, and just swap the pulleys. a few special tools are involved to get the pulley off though.

[jeffcoslacker]

Occaisionally the clutch might be adjusted wrong, and drags when not engaged. You can see the clutch face trying to turn with the pulley, usually in little jerks or chattering when not locked in when that happens. If the clutch is perfectly still and you have the noise, it is the bearing, as said.

Make sure it is the A/C doing it before deciding to tear into it. I've seen numerous times an A/C compressor mistakenly replaced for noise issues, when in fact it was the tensioner arm or pulley or another accessory's bearing reacting to the change in belt load when the A/C clutch went on and off.

[jeffcoslacker]

Personally, I've see those compessors rattle, knock, chatter and jingle for years without anything happening, so if it works well, I'd ignore it. I had one on a GMC Safari van that sounded like pieces should be falling off. But it worked excellent. Was still working fine when I sold it, after listening to the noise for three years.