Squealy Sonoma

[nojj]

My 94 Sonoma develops a high pitched squeal about 10min after start-up.
Coming from up front.
Replaced the idler pulley a couple days ago. (bearings felt kinda rough)
Thinking it's the tensioner. It doesn't sound like a serp squeal.

Any thoughts?

 

[fishin_wi]

could be the alt pulley bearings. best way to find out is have another person with ya when you start it up. Sometimes if you squirt a bit of oil or lube on the bearing it will go away temporarily....I'd take the belt off or loosen it and spin any pullys by hand, see what ya find. goodluck

 

[drwet]

Take the belt off and run the engine. Dont run it more than about 15 seconds because the water pump won't be circulating the coolant. If the noise goes away, it is something that is driven by the belt, or the belt itself. Then you can inspect each of the accessories and hopefully the offending device will be obvious. The other thing you can do is take your mechanics stethoscope and probe each of the devices while the engine is running. It should be obvious which one is producing the noise.

 

[nojj]

Had to cancel a vacation trip, Wife of Nojj is not happy.

The squeal/whine/screech is still there,
after replacing the tensioner, idler pulley, serp, and the water pump.
(Also changed the oil)

One curious thing.
when the aircleaner was removed, the sound got a LOT louder.

Doesn't happen cold, but does when reaching op temps,
or if run for 10 min, then restarted.

 

[nojj]

Finally got it nailed down: a leaky throttle body gasket.

Thanks for all the tips & suggestions for the various problems.

 

[drwet]

Wow. Thanks for letting us know. That's a new one on me.

 

[nojj]

Yup, new one on me and my oldest son the mechanic as well.
Never heard it on a vehicle before, but the sound was somewhat familiar.
Didn't sound like a metal squeal like a flaky bearing.
We were cursing & waving wrenches in the air....errr..... engaging in learned discourse,
then it hit me *ouch*
I'm only a backyard mechanic (My son is the one with the certs)
But I do know construction gear.
Close to the sound I get on my blowpipe attachment with a too-small tip on the house compressor.
Then we replaced a vac line on the truck and the sound got louder.
Put us on the right track.
Quick call to the Zone, and problem solved.
Too late for my previously planned trip,
but at least we didn't have to drop in another motor or something drastic like that.

Hoping other Sonoma owners can learn from our experience.