i have a 94 525i and when I turn the ac on

[Unregistered]

the ac compressor or clutch makes a rattling sound. The lady who owned it before me took it to the dealer and had it all replaced and the noise was still there. Could it be something else. I thought about replacing the pulley. Has anyone had this problemand if so how did you fix it. Or how can I eliminate the parts to see what is the part making the noise. Thanks

[DanDombrowski]

Define "had it all replaced". Did they replace the compressor? Mine is doing the same thing, I suspect the bearings in the compressor. I plan on just using it until its dead and turning up the radio in the meantime, however, it has been over 2 years its been doing this and still hasn't broken, so mabye it is just a loose pulley. I have no freakin' idea.

I'm sure if it breaks you'll hear me ranting and raving about how hot it is tho.

[Tiger]

Could be a bad tensioner rattling.

[RobPatt 93 525ia @122K]

mine does it too, though I'm not sure what pulley it is... and it's been rattling for about 2 years and hasn't broke... though recently I've gained a nice whistle/squeak from among the belt and pulley areas.... going to pull the compressor belt and see if it continues & update later... cheers, Rob.

[andyman32]

I had a '97 E39 from '01 to '02. The entire time there was a rattling noise coming from under the car when the AC was on. But it always worked.

My AC is more bizarre; hot air blows from the top and bottom vents (if I have them on), but the middle vents blow ice-cold. If I just have the top or bottom vents open, then only super-hot air comes out. If I have them all open, hot comes out the top & bottom and cold in the middle. Anyhow... as long as the cold air comes out from SOMEWHERE. :)