i have 2003 tahoe v8 5.3L T
mileage is around 134000
my car started to make this squealing noise few years ago..
it comes and goes away randomly...
whenever i take my car to the shop it stop making this wierd squeal noise..so the tech can not really find out what is causing it..
so i changed the belts...it went away for few month and came back...i changed the idler pully this time...and it's still there..

squeals anytime when the engine is running..means...it squeals even i start up..it goes away...and comes back...anytime...randomly..
it squeals even when i am idling...it squeals when i press the gas..when i prees the gas hard it makes louder noise..and it goes way again...
i really need help here...everybody is looking at my car cause of this squeal...please help...

 

If it comes and goes, maybe it's something load dependent. Does it happen more often at night with all the lights on? How about while the steering wheel is turned? With A/C compressor running (on some vehicles, Defog will run the compressor automatically)?

 

it makes sound even at night or day...
it happens either the ac, heater is on or off..
it happens when the steering is turned or not....
i'm really frustrated with this...any suggestion..?

 

It's not easy when it appears really random and intermittent. The only thing you can take out of the loop is the A/C compressor. Have you tried driving around with that belt off?

 

yeah i know...thats why even the mechanics from the shop could'nt tell...
i dont get how to drive with the belt off...what do you mean by that?

 

Doesn't the A/C compressor have its own separate belt? You can take that belt off and still drive it. Also, if the noise were more of a squeak rather than squeal, it could be coming from the crankshaft balancer. I don't know, it's just a thought.

 

ok.. thanks for the advice...i'll try to do that..

 

You know there is a cheaper way to find the squeal if it is a belt.I have used a little dap of Dielectric Grease.Put a little dab on the outer surface,and a little dap on the inner surface of both belts.DON'T put a lot on the belts.I have done this for many years because alot of these belts do dry out,and get a very shiney surface and a little of that grease cuts the noise out 99% of the time.

 

I was going to say now put a good belt on. Alot of the aftermarket ones are cheap and dry fast.

 

I agree, go with a quality AC Delco belt, I have found that to prevent squealing I need to replace my serpentine belt about 1x a year....
Something else to consider is the tensioner pulley, if it is weak even a new belt will squeal like a banshee, with that many miles I'd replace the tensioner...