99 GA with A/C rumble

Hello. Have a 99 Grand Am, V6, ~65,000 miles. In the past 2 days, when I start the car, (engine cold), and turn on the AC, I will hear an ominous rumble/whine, (with vibration), and if I turn the AC off, it goes away right away. I turn it on again, and it runs fine. Later that night, when everything is cool again, the same rumble comes back the first 1 or 2 times I turn the AC on, then goes away after turning the AC off and on once or twice.
Had the system evacuated and recharged earlier this summer, too. Sure hope that the compressor isn't dying.

Something I should worry about? Thanks for all help!

- Eric

likely the A/C clutch is going west. I'd be concerned, cuz if it freezes, the pulley will, and that means a snapped serpentine belt.

I'll get it in and have it checked out tomorrow then. Not going to risk breaking a belt and then being by the side of the Interstate. Thanks!

Hear ya there!!!!!!!!!!

The clutch only engages when you turn the A/C on, otherwise it is free-spinning, [it is electrically activated]. Since the noise happens when it is turned on, the clutch may have some prob.'s with engage3ment.

As I read this one a certain train of thought comes to mind, but I'm a little tired so its not too clear. Think along the lines of a manual transmisison, it makes noise when the clutch is depressed with the engine running and the car not moving. When you release the clutch the noise goes away. Cause: bad pilot bearing. Is there a similar part on an ac compressor? My manual does not cover ac compressors all that well, its one area that Haynes is sorely lacking in, along with details of the innards of transmissions...

Hard to describe, but the clutch is essentially a spring that "grabs" when the shaft is electrically activated, very similar to the clutch in a manual tranny.

What happens is that the spring armature can rust or fail to "grab" when activated, or worse, grabs when not activated.

Silver...try activating the front window defroster, if the noise happens then I would say it is the A/C clutch. If the noise doesn't happen then you most likely have some other kind of A/C problem. The clutch is supposed to engage when the defroster is turned on to help lubricate the seals of the compressor during the off months.

Let us know.

Thanks, Dan, wasn't too sure about this.