Squeal under the hood

[Chetrick87]

My truck makes the high pitched whining dcreetching noise when its real cold or wet outside. The noise goes away when i accelerate. I changed the idler pully already and the noise is still there. Whats next? Serpentine belt looks good but theres another belt lower that looks crappy.

 

[Buzzcut]

That belt is for the AC compressor. There is also a tensioner on it. My guess the belt is wore out. My 2003 did that and I changed the belt. No more noise after that.

 

[RED TAHOE LS]

Chris, my Tahoe does it when 1st started in cool/damp weather even inside the garage, until it warms up and it's gone. The serpentine belt is very shinny on the back side where it drives the idler, just annoying sometimes but poses no threat. JMHO and good luck.
David g.

 

[MichaelSE]

My squeal was the s-belt, even when I swore it was the tensioner pulley. Mine looked new as well when I bought the truck. I replaced the belt and it stopped for awhile then started squealing again after a few thousand miles.


Turned out that the alternator mounting bolts were not tightened to the correct torque spec, and the alternator pulley was misaligned with the others by a fraction of a centimeter, causing the inside edge of the belt to wear and rub on the pulley. That's what was causing the squeal. I found this out by accident when I changed my alternator, tightened the bolts to spec, and the squeal went away completely.

That belt is for the AC compressor. There is also a tensioner on it. My guess the belt is wore out. My 2003 did that and I changed the belt. No more noise after that.

NNBS trucks don't have a tensioner on the A/C belt. You need a belt tool to take it off and put it on

 

[Chetrick87]

I thnk if it was something not tight **** the alt bolts it would be noisy all of the time. Instead its only when its wet or under 35 degrees out. I dont think i saw a tensioner on the ac belt. Thats the one closer to the ground right? Looks like a pain in the ass to change.

 

[08HoeCD]

NNBS trucks don't have a tensioner on the A/C belt. You need a belt tool to take it off and put it on

Actually, pre-2009 NNBS do have the tensioner for the a/c belt.

 

[MichaelSE]

Actually, pre-2009 NNBS do have the tensioner for the a/c belt.

Interesting, I had no idea. Thanks for the info man.

 

[08HoeCD]

Interesting, I had no idea. Thanks for the info man.

Sure. I realized this when I was doing some quick research on YouTube to prepare for changing my serpentine belt and the a/c compressor belt on my 2008. No idea why they did away with the tensioner for 2009+---seems like a real pain in the arse to make the change in later model years.

 

[Buzzcut]