C5 x7 - faulty compressor?

[Agour]

Hi everyone!

The AC started making a scratchy sound on my car recently.

When the engine is being revved, the noise goes away.

Turn the AC off and the noise goes away...

Turn the AC back on, noise comes back, and the AUX belt starts jumping around.

I'm assuming it's the compressor clutch - or could this be a red herring and it's the actual compressor...or heck, maybe even the tensioner?

Thanks!
Paul

[mickthemaverick]

Your description certainly suggests a compressor fault, the clutch or the compressor are possibilities and investigation is necessary to determine which. Remove the belt and check the other components for free rotation and then the compressor clutch for end float and 'rocking' on the shaft. They are fitted with a shim to set them correctly and that may have sheared. Good luck

[Agour]

Your description certainly suggests a compressor fault, the clutch or the compressor are possibilities and investigation is necessary to determine which. Remove the belt and check the other components for free rotation and then the compressor clutch for end float and 'rocking' on the shaft. They are fitted with a shim to set them correctly and that may have sheared. Good luck

Whizzed the belt off and the outer wheel seems to spin freely.

The inner wheel would move under pressure, but wouldnt spin freely (although I assume this is normal).

Couldn't really feel any movement in it.. maybe a slightly bit of side to side but not very much

[ozvtr]

The AC started making a scratchy sound on my car recently.

Turn the AC back on, noise comes back, and the AUX belt starts jumping around.

Would you describe the sound as "metal on metal"? As Mick says, the clutch faces are shimmed to give the correct clearance when the clutch is disengaged. But the metal faces of the clutch can ware and cause the clutch to slip when it's supposed to be engaged. If this is the case, just removing a shim or two may fix the problem.

[Agour]

I don't think it sounds like metal on metal... It's seems to be more the belt.

Once ac is engaged, the belt goes wild for a few seconds, flapping all violently.

Seems to calm down a little then, but still making more noise than with AC off.

My suspicions are if it was the bearings inside the unit, there would be play on the shaft.. and/or the noise would be consistent.

Which makes me think the clutch might be a bit sticky, and isn't always fully engaging. That would throw the balance off and cause the flapping

[Lenny]

Check the alternator clutch pulley.