Loud Squealing When I Accelerate

[Shoffner1226]

I have a 2008 Yukon that has been squealing loudly especially when I accelerate for months now and its driving me crazy. I've gotten the idler and tension pulleys both changed, new belts, and yesterday and new water pump and its its squealing. There's a new alternator on too and I have no idea what it could be.

 

[Doubeleive]

does it do it if you are parked and just rev it up?

 

[Shoffner1226]

does it do it if you are parked and just rev it up?

Yes! If its cold outside it'll do it on startup too

 

[Doubeleive]

Yes! If its cold outside it'll do it on startup too

then you need a helper and a cheap stethoscope that you can get from almost any auto parts store, have the helper rev the engine while you listen with the stethoscope to locate the sound, if you are still unable to determine the source then remove the belts (all of them) and then try spinning parts to see if one makes any noise. if not then put the ac belt on only and see if that is it. the ac belt may be a stretch belt so if you need to take it off lisle makes a tool to remove it or reinstall it.
this should have been a "first step" before firing the parts cannon and replacing things that were not the issue.
you could also try just taking the serpentine belt off and see if the it's the ac belt making noise, if the ac belt has a tensioner that is a common noise maker.

 

[donjetman]

@Shoffner1226
The crankshaft pulley is 2 pieces held together by rubber that gets old and can fail causing misalignment squealing, etc.
I changed my pulley, etc last summer as preventative maintenance: https://www.tahoeyukonforum.com/threads/valley-cover-crank-pulley-etc.149036/

 

[Doubeleive]

commonly referred to as a harmonic balancer, if all the belts are off and it is still making noise you can use the stethoscope to verify