Challenging squeal

Hi guys,

I'm a long time reader, but not much of a contributor. I do however, hope that somebody can point me in the right direction with my issue.

When cold, my vehicle makes a whistle/squealing noise that goes away when the vehicle is warmed up. All through spring, summer, fall, the noise goes away, and only reappears when the mercury starts dropping. I've looked over many posts relating to squealing noises, and none seem to fix the issue. The last idea was the waterpump bearing was on the way out, but i'm coming in to my third 3rd or 4th winter with the noise, and figure the waterpump should have died by now. My local NAPA guy (very helpful) believes that, perhaps, the waterpump gasket is bad, and when cold, it contracts enough to create a small gap, which will whistle until the engine has warmed up and the pump has reseated. This may seem a long shot, but i've also notived that i lose small amounts of radiator fluid through winter but not in summer. The leak appears to be weaping from the waterpump.

Any thoughts?

Thanks!

BTW.... 98' V6 stick, 4x4, S.....

Idler pulley bearing?

In regards to the idler pulley bearing, when i changed out the serpintine belt, the pulley appeared to turn smoothly without any noise. I guess that is still a big possibility but would the noise be consistent, even when hot, if the bearing was shot? A coworker had a quick look with me and suggested the viscous coupling on the fan could be done also....... i'm now further confused:banghead:

I think it could go away when warm, and I think I saw a thread here within the last year or two where it behaved that way.

The word "whistle" makes me think intake manifold gasket, too, but usually there are driveability issues when the IMG is leaking.

I'm not buying the water pump gasket at all, though.

Let us know!

Here's my thoughts, for what it's worth:
I actually thought also of the fan due to the fact like your friend said, that there is a temperature sensitive fluid in that fan assy that varies the speed of the fan rotation. That being said, on start, that makes the fan spin fast first off until it regulates itself and slows down (that's the 'vroom'ing sound for the first minute or so after start). It only usually takes the fan a few minutes at best to regulate itself, so that may or may not coincide with your noise.

My thought on the water pump - if you have noticed it leaking from the weep hole, that does show it's worn and needs to be changed at some point soon, especially if you have higher milage and might need a timing belt anyway - probably good idea to do in conjuction.

Mark

I agree with getting that water pump fixed asap, too. All aluminum engines and the 4L-30E tranny don't like heat! Also, if the bearing siezes, it takes the timing belt with it.

I think might have 2 different issues. If you see coolant out of the weep hole then it should be replaced. Might as well do the entire timing belt service while you're there.

The squealing and whistling sounds aren't really in the same realm as far as sounds go in my opinion. I replaced my idler pulley a couple of winters ago. I drove around with the squeal for almost a year. It got bad during the colder months due to contraction of the bearings. As the truck got warmed up the squeal would go away. You can replace the pulley in a few minutes and the part isn't expensive. If you drive a 98 and haven't done it yet consider it preventive maintenance.

Whistling and no codes? It could still be a IMG.

You say you've made some repairs in your OP but you don't mention what you actually did.

Maybe it was your idler pulley bearing I was thinking of, Pharm...

I have a 2000 passport that is doing the same thing. I replaced the idler pulley cause it's a $12 part at autozone, and about a 10 minute install even for someone who isn't a mechanic. Didn't fix the problem though. I can take the S belt off and the whistle is gone, not the IMG then. Fan clutch makes sense but is a more expensive part. Wonder if anyone has a procedure to just grease it back up for the repair vs. getting a new fan clutch?