I've posted this other places with no answer, so I figured I would try here!

I have a 1999 Silverado that has a chirping noise coming from under the hood. The chirping only starts once the engine has warmed up and gets faster with engine speed, but doesn't seem to be as fast as the belt is moving.

What I've Done So Far:
1. Replaced drive belt and tensioner
2. Replaced compressor belt and tensioner

Still have the chirping noise and can't tell where it's coming from. I've read post that it could be the water pump bearing going bad and I've also read that it could be the camshaft sync sensory bearing going bad? If anyone could help me, I would really appreciate it, as I hate to pay someone to work on my truck!

 

The kid down the street from my dad's house had a chirping noise too, but as he accelerated it got worse... more like a screaching noise.Mine started it and I found out my Idler pulley bearing was dry so I degreesed it and repacked it with grease andfixed it. The kid down the street replaced his Idler pulley which as dry, but still had the chirping noise. So he ended up replacing the waterpump tooand that fixed it.

 

Thanks. I bought a new idler pulley the other day, but it's only the pulley. I unbolted the old one off the truck and it comes off as one piece. There is something in the middle of the pulley that the bolt goes through and I can not get the bolt out. Anyone had this problem?

 

Is it like a slotted washer on the backside of the pulley? If it is, what I do is put the bolt on the front side in a socket in a vice and take a flat bladed screwdriver and turn it so that it backs off. And if that does not do it, thenuse 2 flat bladed screwdrivers and wiggle it off. Then when you are putting the new Ider pulley on be sure to put the slotted washer back on the blot on the backside as it came off. And if that does not cure the chirping then look at the water pump. That is the best advice I can tell you. Good luck.

 

That's it, I finally got the washer off and put the new pulley on. The sound was worse (constant high pitch squeal)...but , that may have been from the WD40 I sprayed on the old pulley before changing it out. I cranked again this morning and the constant high pitch squeal was gone, just back to the intermediate chirp? Could the WD40 getting on the belt made the sound worse? I know it's something in the main drive belt because I pulled it off last night and ran the truck for a few seconds and no more noise. I just can't figure out where it's coming from!!! Driving me nuts!

 

try some wax on the belt..... a stick of wax on either the outside of the belt or the inside while it is running will tell you if you need to replace the belt or if it is a pully problem......just remember to watch your hand

 

I tried soap on the back side (smooth side) and nothing changed. I just put a new belt on it 6 months ago.

 

Here's a link to a video I took with my digital camera. This noise persist after replacing both belts, both tensioners, and the idler pulley. Does this sound familiar to anyone???

http://i396.photobucket.com/albums/pp48/bt...nt=Chirp001.flv

 

Alternater bearings, waterpump bearings? It sounds like rough bearing to meallowingsomething to rub against another piece of metal.I do not know other than that. I made all my suggestions earlier. Maybe you could ask Argon. He might have an idea. But atleast he high pitch squeal is gone. If you figure it out let us know.

 

Take the belt off and turn the pulley on the Alternator, water pump, and everything else it might be. Turn them all a lot of times. If you still cant find it try using a belt or something to put pressure on the pulley's wile you turn them. If you still cant find it make sure there isn't a smoke detector around. LOL just kidding have ever heard one and didnt know where it was coming from?