Nocking noise when AC is turned on

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05-18-2009 | 01:53 PM

1999_Saturn

Thread Starter

Junior Member

Joined: May 2009

Posts: 10

Knocking noise when AC is turned on

I have a 99 Saturn SL2 that has a Knocking noise when I turn on the AC. When I turn off the AC, the Knocking noise is gone. Any Ideas?

Last edited by 1999_Saturn; 05-18-2009 at 02:03 PM.

05-18-2009 | 09:52 PM

sw2cam

Senior Member

Joined: Mar 2006

Posts: 3,278

From: Arizona

Hood open engine running A/c off look at the tensioner belt

While your still looking at the tensioner and belt have someone other then you turn the A/C on.

Whats the tensioner and belt doing now?

05-20-2009 | 01:43 PM

1999_Saturn

Thread Starter

Junior Member

Joined: May 2009

Posts: 10

When the AC is turned on, the belt tensioner pulls about half inch and the belt seems jumpy.

05-21-2009 | 11:39 PM

turbokid

Junior Member

Joined: May 2009

Posts: 7

From: Overland Park Ks

sounds like a locked up compressor. If you have mechanical ability slip the belt off and give the a/c compressor a turn. If the clutch is catching or completely locked up then you will need a new compressor.