Stumped

[needlenose]

My 92 recently started a dry-bearing type of sqeak; almost a chirping. It gets worse/louder as engine rpm increases and drops immediately when it idles down. It follows the rpm exactly. I took off the belt and spun the idler pully. It felt dry, so I replaced it. A week later it started up again. I spun the water pump and the fan pully and both felt "lumpy". So I replaced both of them. Two weeks later the chirp is back. I just removed the alternator and gently spun it to about 1K rpm with an impact. Smooth as glass and takes its time spooling back down. The chirp does not change when turning the A/C on and off. So I don't think it is the A/C idler bearing. I also took off the idler arm and inspected it. There's no metalic powder coming out of it, no shavings, no apparent wear. It flexes from stop to stop smoothly and without protest. There is no flop in it at all.

It doesn't squeak it all the time, and sometimes it cuts in and out very rapidly when driving down the highway. This is driving me nuts. It *never* does it when I have time or tools to pull it apart. It did almost all the way home yesterday. By the time I got home, it had stopped. I've started it up about 5 times since; no chirp.

[Tacoclaw]

Did you replace the belt itself?

I can't remember exactly what it was but somewhere I read that throwing something on the belt while it's running will stop it squeaking. Baby powder maybe?

[needlenose]

Sorry, yes; I replaced the belt. It has about 150 miles on it now. I actually bought it when I bought the idler pulley. I was about 200 miles from home and figured if the pulley locked and the belt gave out, I could replace both on the side of the road.

[Tacoclaw]

Hmmm, have you messed around with the injection pump lately? I seem to remember someone saying the injection pump gear makes a squeaky noise when it cracks.


Not to doomsday this or anything, but it may be worth popping off your oil fill and checking for anything obvious. Is the truck an automatic?

[needlenose]

Nope. The truck is bone stock. I haven't jacked with anything. The only thing I've done to the engine is change the oil and check the valve lash. Once I had to replace the little plastic timing plug on the back on the back of the case. But I would think if something that major had happened, it would do it all the time, right? I'm going to let it sit for a few days and try to get it do it again. This last time, it was run for about 45 min and normal operation, then sat all weekend, then started squeaking as soon as I fired it up on Monday to come home.

Stock getrag 5-speed.

[delsilver]

carry a spray bottle with water in it, next time it squeaks spray the belt and if stops the belt is the problem.
have you used belt dressing, if so that makes an ugly sticky mess that took me an hour to clean off. found out after you shouldn't use it on a serpentine belt.
Del

[Tacoclaw]

I'll think on it some, not a whole lot of easy things it could be.

Try taking off your oil fill cap next time and see if it gets any louder.

[CAJUN 93]

next time its making the noise, loosen the tensioner and take the belt off and start the truck. you don't have to take it all the way out, just get it away from the crank pulley. if the noise goes away it's belt driven.

[needlenose]

I did this when I installed the tensioner pulley(the first part I replaced) and thought, "See how clever I am? That proves it. No belt no squeak; it was the tensioner.".

A week later it was back.

The fact that it will stop by the time I get home makes me a little suspicious of it not squeaking without the belt. It doesn't always squeak with it either. I'm just hoping I can get it to start up again. I have a 500 mile round trip to make in a week and a half.

Thanks for all the input guys! If I haven't gotten it to squeak before I leave, I'm just going to take as many tools as I can and when it starts, I'm going to pull over and take it apart. My wife is going to love me!

[Remps]

I think honey works better for stopping a squeak than belt dressing for V-belts. Sticky mess though.