Thoughts? Squealing Woes

[vbora01]

98' AEB 1.8t, 212k miles on the clock.

So I've been able to live with it for the past year or so, but after last night I just can't stand it anymore. ONLY WHEN COLD, my car has been making this intermittent squealing noise. It doesn't sound like a belt is slipping. And it is not RPM dependent somehow, yet it goes away under 25 mph, and when going off the throttle. What I suspect is the power steering pump:
1. Because the squeal goes away COMPLETELY when I'm turning, or moving the steering wheel back and forth.
2. Because the pump just sounds loud
3. I suspect the OEM manufacturer of the steering pump was NOT KYB I was expecting Koyo or ZF (with more lean towards the latter.)
4. After about 20-30 minute of driving it'll eventually subside, and go away completely.

What I've ruled out:
Viscous fan coupling and bearing, replaced fan and it's super smooth, bearing (amazingly) spins freely and doesn't feel "gritty" when rotated
Alternator (poor man's stethoscope)
A/C Compressor, which doesn't ever need to be run when it's 30 degrees out.

What could be it instead of the pump:
The accessory tensioners
Water pump?
A wheel bearing???

So can anyone describe the operation of the power steering pump in relation to engine RPM and speed? Is it clutched? Is the pump bearing itself serviceable? Could it be a lack of oil from a clog in the line restrictors? I'm just trying to get an idea for it. I hate squeals and thrills, they're the hardest to diagnose!! Unless I ride with the hood open, sitting atop of the engine with a friend driving, I don't know if I'll ever find it!

Thanks in advance!

[ylwagon]

Does it do this in Park, without the car rolling? You can rule out accessory rollers by removing the serp belt and seeing if the noise is gone.

[vbora01]

Can you drive the car down the road with the alternator not rotating?

Now that I think about it, the noise is speed dependent, not engine RPM dependent (would that rule out anything related to the engine?) It sounds like metal on metal. No it does not make the noise below 25 mph, or idling. It's a 5 speed too.

[99vwpassataeb]

If it doesn't make the sound while idleing in neutral or when you rev it up in neutral at a stand still and no noise then you can eliminate the serp system..sounds like a wheel bearing..

[vbora01]

Can a wheel bearing be intermittent like that? When cold it squeaks? but after being warmed up its fine?

Well look at that lol...

Maybe I should put the car up on some jackstands and start revving!

[ylwagon]

Can you drive the car down the road with the alternator not rotating?

Yes, but with an AEB you won't have the water pump turning, so its best to do any such tests breifly.

[VAGguy]

Interesting. Mine sort of sounds like that when cold. Mine is more of a constant whistling sound that starts at about 20-30 mph, then all the way to a stop. It will keep doing it until about a half mile unless I firmly apply the brakes to a complete stop. Then it will not do it after that. Only in sub freezing temps though. For about 3 yrs.

[vbora01]

Interesting. Mine sort of sounds like that when cold. Mine is more of a constant whistling sound that starts at about 20-30 mph, then all the way to a stop. It will keep doing it until about a half mile unless I firmly apply the brakes to a complete stop. Then it will not do it after that. Only in sub freezing temps though. For about 3 yrs.

WHISTLING! That's what it sounds like, sheesh, took me long enough to think about what it sounds like (thank you!) Mine also starts right above 25-30 mph, consistently. I'm going to raise the front end in a weeks time with the wheels off and try what the guy does in the above video. It comes from the left side, I've been all under the engine, looking under the hood, using my poor man's stethoscope on every "bearing" surface and can't find anything that sounds irregular. The power steering pump sounds completely fine, and runs completely fine, and I imagine it would HAVE to be RPM dependent, or any belt system for that matter.

I'll see if I can't make a little video once I get the wheels off the ground. While I know it varies from shop to shop, what would taking the knuckle to a machine shop to press out the old bearing and new in cost? Buying the specialty tools (to do it right) would far outweigh this cost I think... I just hate the idea of having to take the front end apart: AGAIN. I just did control arms and shocks, and what a PITA to do it all at once. Not to mention it' probably recommended to do the other side too because the idea is that if one fails, the other's probably close behind (sometimes.)

Thanks everyone for the suggestions and responses!

[walkthenrun]

Do you think it may be the alternator bearing. I had an older car that would squeal during cold startups, when there was more load on the alternator. My squeal went away after I replaced the alternator. Just a thought...