98' Altima AC squeaking noise with AC off

I have a 98' Nissan Altima that makes this horrible loud whiny squeaking noise. It really strange that noise is stop when I turn AC is on and back when I turn the AC off. Any idea what it could be?:banghead:

Maybe the noise is from the Alternator belt. In any case maybe the change in the noise is caused by change in engine speed with A/C on and off.

There more noise then it change in engine speed, but it sounds normal with AC ON (unless compressor stops for few seconds and noise temporary back)
With AC off noise is constant
??????

checking belt tension/changing the belts are the simplest/cheapest thing to do 1st...

then i'll suspect the ac clutch/pulley area next...

The belt seems OK, but looks like that clutch is stock and not moving till turn AC on.
The sound is really dry, should I put same grease and how......

The belt seems OK, but looks like that clutch is stock and not moving till turn AC on.
The sound is really dry, should I put same grease and how......

clutch on the compressor pulley shouldn't move until the AC is on...so that's normal...

get a 2nd opinion on the belt; is it the original belt as well? then mebbe it's stretched/worn & just needs to be re-tensioned.

when the AC loads up on the belt, it might be pulling the tension tighter so the noise goes away... and when it's off, the belt's too loose... that's my internet guesstimation (wish I was there in person)

The A/C clutch is touching the compressor drive face when it isn't engaged and making a squeek. Correct air gap adjustment between these two A/C clutch parts prevent this noise. When the clutch locks and starts turning the compressor the scraping stops because the pieces are locked together as they should be. The noise isn't from a belt slipping.

http://nissaninfiniticlub.net/photopost/data/500/4964ac_clutch.JPG

so, mebbe blast some brakecleaner around that area to free up some trapped dirt that may have been clogged in between the clutch face & pulley... then do a visual on those parts?

Seems you guys absolutely right that the AC clutch is stuck to compressor.
Is there some way that I can correct that air gap, clean the dirt and put lubrication without removing parts.

Nice illustration and step-by-step. You can un-bolt the compessor and move it enough for the tool to fit without removing the hoses or loosing any freon. AutoZone should have the tool to loan you. If you pull the drive plate away too much you will make the air gap too wide and need the install tool to push the plate closer.

Hey guy,
Here the continue of my story
I followed your advice and clean the clutch and now it’s moving and attaching perfectly. But unfortunately same sound still there. My neighbor said that it look like the sound of ether un-greased of broken barring in compressor poolly. It seems to be an access there if I remove the left wheel there, but any idea that I should de exactly, besides of course going to AC compressor shop.
Thanks again and really appreciate your advices