Sierra Engine Noise - Chirping , Squealing

[shamus]

have a 1996 gmc suburban k1500 1/2 ton 4w, the belt started squealing 2 weeks ago and the amps are dropping. i just replaced the belt and the tensioner also put on a new alternator, all the pulleys are free-spinning and clean. even put a straight edge on to make sure all the pulleys are aligned. what else can i check this is driving me nuts.

[ProTech]

Even if all of the pulleys are free spinning, that doesn't mean there couldn't be a problem with one of the bearings on any of those pulleys. I've seen idler pulleys make this type of noise when the bearing goes out in them, and sometimes they won't make any noise without a load on them, such as the belt connected and engine running.

Just turning them by hand probably won't find the squeal. You might want to try listening to each pulley with a long screwdriver while the noise is happening, obviously NOT putting the screwdriver ON the pulley itself, but any metal it's attached to (bracket, component, etc). This is the easiest way to locate which area is causing the problem.

[032500HD]

I have a constant noise, somewhat like a chirp, that I'm having trouble finding. I ran the car with both belts off and no noise. Then ran it with just the ac belt on, still no noise. Put a new serpintine belt, tensioner, and ider pulley on and it still makes the chirp noise. Any thoughts? I did notice a small puddle, aprx 4'', under the car this morning. Could the noise be coming from my water pump?

2003 GMC Sierra extended cab 2500hd 4x4, gas 6.0L

[wildman]

Could be the water pump, especially since you're seeing leakage. When you had the belt off did you shake the pulleys and idlers to check for play?
Idler pulleys and alternator bearings are the first place I look when there's rogue noises. Take a piece of small hose and use it to listen around the engine compartment. Be careful about getting clothes, fingers, or the hose around the moving parts. The hose will allow you to narrow down the general location of he sound.

But, if you're leaking it needs fixed even if not the source of the sound- they never get better, always worse. I would use a piece of cardboard under it and look exactly where it's leaking.

[TerryAuto]

I have a constant noise, somewhat like a chirp, that I'm having trouble finding. I ran the car with both belts off and no noise. Then ran it with just the ac belt on, still no noise. Put a new serpintine belt, tensioner, and ider pulley on and it still makes the chirp noise. Any thoughts? I did notice a small puddle, aprx 4'', under the car this morning. Could the noise be coming from my water pump?

2003 GMC Sierra extended cab 2500hd 4x4, gas 6.0L

Ya, i think the leaking water pump is your problem. Coolant contaminates the belt and makes it chirp.