I've been a having a squeal lately when I fire the engine up cold, but it always went away after it warmed up a little. Now for the last couple days I've started the engine up cold and the front of the engine squeals and keeps squealing after the truck warms up. I know its not because of the cold because we had 62* weather the other day and it did it then. I thought my alt was going bad, took it off and found one of the bolt holes was egged out. Water pump was making a noise when turning by hand too. I replaced both of those and I have a month old tensioner on the engine and it's still making a nasty squeal. My next guess is the belt. I did take the belt off and ran the engine and the noise went away. Fan seems good and so does the AC comp, I kick in the AC or defrost and i get no change in noise. I need some help with this one, it's going to drive me nuts.

Are the Gatorback belts good ones for reducing noise?

Thanks!

 

make sure your exhaust manifold is tight, my friend had the exact same problem and replaced the exact same parts and it turned out to be that the manifold was loose. just a thought.

 

Didn't think about checking that, I'll try it tomorrow. It seems to start off quiet and get louder when the engine warms up. Could be it.

 

also check the belt tensioner.

 

The bearing for the fan goes out and will give you a noise also. Part #6
Drive Pulleys Diesel Engine
6 BEARING, Idler Pulley
442 9639 1 ETH DBB
442 9639 1 ETC DBB
442 9639 1 ETC
442 9639 1 ETH DBB

 

The tensioner is only a month old, but I am not gonna rule it out. I did check it and it sems fine spinning by hand. I have a friend I by parts through and he'll warranty it still so I might do that But I am still leaning towards that it might be a bad belt. I might see if my friend at the parts store can get a belt for a non AC truck so I can try that out. Might rule out the AC compressor then. If it still squeals w/ a non AC belt then I know the AC comp is not bad. Gonna try at it tomorrow.

 

Thanks for the drawing BigIron. Didn't realize there is that much to tha fan pulley. The truck does have 144K on it so it might be time for a few things to be bad. I'll take it apart tomorrow afternoon.

 

With the engine running, give the belt a shot of Brake Clean. If the noise changes or disappears momentarily, you know it's a belt problem.

 

Some of the lifetime warranty belts will make noise. They mfg them with such hard dense rubber that they will squeal no matter what you do or how much you adj the tension. I had a new a/c belt on a honda that drove me nutts....replaced it w/a cheap one and no more noise.

 

I'd blame the belt too, if it squeels only on start up likely its cause the grids are cycling and placing a load on the alt and causing the belt to slip, if you want to eliminate the AC compressor as a culprit, unplug the hi-low switch located on the acculimator/dryer (big round thing next to the firewall pass side with a sensor screwed in the top of it) this will make sure the compressor does not engauge or place the heat selector on the floor setting.

I believe its your belt, if you spray water on it when its squeeling and the noise stops ...its a belt

 

Had the same problem I put on 2 new belts,new water pump,alternator,ac compressor, the bearing behind the fan that cost 200 bucks and finally the 3rd belt was one hanging in the barn the noise went away.

 

Could also be low power steering fluid, or a noise in the PS pump itself...

 

Matt are you sure its not a loose nut in the cab?

 

Ok, I tried your idea with brake clean this morning before going to work and while spraying the noise would start to go away. As soon as I stopped spraying the started coming back. So I believe it is the belt. Thanks!

No the PS is fine, it's defiantely coming from the front, plus I think the PS pump is gear driven and not belt driven on these trucks.

That loose nut done fell off a long time ago!

 

I replaced once the belt on my '01 with a Gatorback. It was the noisiest belt I've ever dealt with. Went with cheaper type and got no problem at all.