knocking sound

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knocking sound

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Chevrolet >> Chevy Trucks, Vans & SUV's >> Trailblazer >> knocking sound

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knocking sound - 6/5/2007 10:55:32 AM

mgunim7631

Posts: 4
Joined: 5/30/2007
Status: offline

I hear a knocking sound that i presume comes from the front of my engine. I think it comes from the fan area and it is itermitent. Anyone ever experienced the problem and if so, what is the fix?

Post #: 1

RE: knocking sound - 9/9/2007 12:49:23 PM

mwall1516

Posts: 2
Joined: 9/9/2007
Status: offline

I am having the same problem. I hear a knocking noise in the front end only when I am idling. I notice it the most when I am at a drive-thru because my window is rolled down. I don't think it is a value because it does it at random times. I went to my local mechanic the other day. When I pulled he heard the noise and said he hadn't heard anything like that before. Then the noise stopped. He wanted $72 dollars an hour to figure out what the problem was. Any ideas?

(in reply to mgunim7631)

Post #: 2

RE: knocking sound - 9/30/2007 7:25:51 PM

rmczyk

Posts: 9
Joined: 9/30/2007
Status: offline

Its the fan clutch. Common wit this vehicle both Trailblazer and envoy. the knock only occurs at idle. If you give gas it goes away. Problem Is when vehicle is not yet warmed up I believe. Mine does it too. Friend had the dealer change his fan clutch.

(in reply to mwall1516)

Post #: 3

RE: knocking sound - 10/26/2007 3:25:20 AM

clipps768

Posts: 1
Joined: 10/25/2007
Status: offline

bad idler pulley.

(in reply to rmczyk)

Post #: 4