At first I could only hear the squealing at start up and then it would go away after the engine warmed up. Then the squealing went away at start up and now when I pull into my driveway, I hear the squealing and it's been back and forth like that for a good couple weeks now.

I spray down the belt with some water when I first notived the squealing a couple weeks ago and it made no difference. I just sprayed it down again and now the squealing goes away (and returns when the water dries up, no surprise). So I'm thinking it's one of the pulleys and not a belt/belt tensioner issue. In fact, I'm leaning towards the idler pulley because it seems to have some wobble at visual inspection but I'm not sure if that's within tolerance.

I hate to just throw parts at it especially since I have not been able to duplicate the squealing consistently but I bought our 08' Burb LTZ used with ~135k on it last June (currently has ~140k) and while I got it checked out by an independent shop before I bought it, I don't know much about it's maintenance history. Any other diagnostic tips I could try or any other symptoms I could be on the look out for to better diagnose? Would this be something that's ok to wait on?

 

belt's aren't too much, and at 135, I don't think it would hurt to throw one on there.

 

I too suspect the take up or idler pulley is your issue, its loose and puts slack in the belt allowing it to slip... when you put water on it, the water acts like lubricant and allows the belt to slip more easily due to less friction, water dries up belt gets traction and "skids" when it finally slips...

I do my belt and air filter annually, I know some say must be nice to have that kinda cash to throw away but its cheap insurance ~$50 for belt and filter... I do the AC belt less often...

I'd have to say the most common thing I see on the road while sitting in traffic aside from crash debris is shredded serpentine belts..

 

I second the pulley issue, drop the belt and spin the pulleys when its cold and when its hot. YOu will find your culprit.

 

any special process to replacing these belts? I checked mine for cracks and at 100,000 didn't find any significant wear/tear. but I'd rather not find the weak spot 2 hours from home hauling a 6,000 lb trailer...

 

Thanks for all the responses. I'll definitely change the belt while I'm at it. It actually looks in pretty decent shape. You'd be hard pressed to find any cracks but since it's gotta come off anyways, I'll switch it out.

Sabrtooth - here's a video that applies to 07-13 silverados on changing the tensioner but it also shows how to remove the belt. I would think the process for burb/tahoe would be pretty similar. Looks like you just need a ratchet to release the tension from the tensioner and the belt gets loose enough to just slide off. You can find the belt routing guide in your manual.

 

A ratchet with an extra-long arm makes for an easy belt change. I sprung for the $30 kit which contains the ratchet, extension handle and 4 or 5 custom sockets. Having a 2-foot+ lever makes it real easy to hold the tensioner while you seat the belt.

And while you're buying a serpentine, make it 2 and throw the spare in the back of the truck. I have spares in all my vehicles. I refuse to let myself get stranded by a silly belt.

 

Good Deal. I'll pick one up in a few days. I have a 3' breaker bar style wrench I use for lug nuts and suspension parts, so that should work here I think.

thanks

 

Spare belt is a great idea. I'm cheap (frugal) so I keep my old one for emergencies as long as it's still usable.