Mechanics

WHERE IS THE SQUEEK UNDER MY HOOD COMING FROM? IT'S DRIVING ME NUTS!

2004 GMC Yukon • 110,000 miles

When I hit bumps in the road (and sometimes when it's smooth) I hear a repetitive squeaking sound coming from the middle to left passender side under the hood. It almost sounds like when you run a squeegy over your window over and over again. I had this problem less than a year ago and I took it in to the dealer had the shocks replaced. I thought that fixed it, but within a month the squeak was back. I decided to do it myself and got out and greased everything I could. And it worked! Until a week ago - it started again and nothing I do now seems to help. It won't squeek when its parked - no matter where I try and bounce on it, so I don't think it's the shocks. It's not a squeal like the brakes are bad. Any suggestions?
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Jenoncape
February 5, 2012.



Shock absorbers don't squeak unless a mounting bolt is loose. When they're getting weak, they will allow the suspension to travel up and down further which can aggravate what is squeaking.

If it doesn't make the noise when standing still, you might try coasting down a hill with the engine off to see if the noise really is suspension-related. Be aware you won't have power steering or brakes so you'll need both arms to steer and a really heavy foot to stop. If the noise doesn't occur, look for something rubbing with the engine. If an engine mount is collapsed, the fan blade might be rubbing on the shroud around the radiator.

If the noise does appear to be suspension-related, control arm bushings, ball joints, and inner anti-sway bar bushings are probably the most common causes.

There is a tool you might be able to borrow or rent from an auto parts store that borrows them called the "Chassis Ear". It is a set of six microphones, a switch box, and headphones. You clip the microphones to suspect points, then drive around while listening with the headphones. You can move the microphones around to zero in on the source of the noise. Be aware that many mechanics have never seen or even heard of this tool. Suspension and alignment mechanics use it to find rattles, squeaks, and other noises.

Caradiodoc
Feb 5, 2012.