Belt squeal for first 30 seconds when cold... most likely culprit?

[Thoragaverung]

Hi,

I have a belt squeal on cold startup, that changes pitch with RPM, and goes away after 30 seconds or so.

I replaced the water pump and serpentine belt tensioner/pulley a few weeks ago. I have not swapped out anything else, including the A/C tensioner pulley.

My 323i does not have an additional idler pulley in the serpentine chain.

Power steering does have a tiny bit of seepage somewhere, haven't found the source. Not even enough to spot the driveway, just dampness on the PS hoses and rack.

What's the most likely thing to go? I wonked on all the other pulleys before installing the new belts and nothing seemed to have play. And why would it stop making noise after 30 seconds of running? If a pulley bearing is bad, you'd think it wouldn't quiet down.

thanks,

[jclausen]

remove the belt start the engine see what the noise does

[Thoragaverung]

I'll for sure remove the A/C belt to see if it's in that chain. I'm wondering what & how I should check in the serpentine path ifthe A/C path is fruitless.

[NuruiGumi]

Spray a little water on the belt, if it goes away at least for a few seconds, it's the belt itself getting old or it's not aligned correctly. If it still squeaks. It's something else, probably a pulley.

[bluptgm3]

Typically, this is caused by a lazy/damaged Tensioner. Did you replace the tensioner or just tensioner pulley? The belt, is it the exact same length as the belt that came off?


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[Thoragaverung]

I replaced the tensioner assembly with a "Duralast' unit. Could it be an issue?

[Eric93se]

Yeah it could be bad. But I would remove the belt and re-seat it, make sure it falls into the grooves nicely.

[Thoragaverung]

Diagnosed it: I put one drop of electrical motor lubricating oil on the front alternator bearing and the sound stopped. So, now I have a nice new alternator on order...

[Fatbellyz4]

Is the belt tight enough?


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[bluptgm3]

I replaced the tensioner assembly with a "Duralast' unit. Could it be an issue?

Ummmm…INA is/was OE supplier for E36.


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[Thoragaverung]

So yeah, it wasn't the alternator. Replaced it, didn't fix it. It's charging better, though.

I think it's the power steering pump.

Item:

I hit a hard corner today at speed and it squealed. Silenced once I straightened out.

It squeals on startup -- and my wheels are usually turned when the car is parked, because my driveway is tight.

Are Meyle PS pumps any good?

[bluptgm3]

I think it's the power steering pump.

Are Meyle PS pumps any good?

You should check out a mechanics stethoscope for isolating problems.

Looks like that might be your only choice.
...except -
https://www.rockauto.com/en/catalog/...ring+pump,7380


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[FiberFast]

You should check out a mechanics stethoscope for isolating problems.

Looks like that might be your only choice.


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Im sorry my ears are bleeding, what did you say? You want him to what? Love you man, don't ever put the stethoscope on belt drive bits...

[Eric93se]

Try changing out the fluid. Takes ATF.

[zohaibrose]

Belt, tensionner pulley or something else

[Thoragaverung]

Intermittent problems are the worst. If it kept making the sound I could locate it for sure.

Everything else with this restoration has been straightforward...

[Thoragaverung]

FIXED!

I was staring at it and noticed slight scuffing on the smooth side of the nearly-new belt.

There was no such scuffing on the A/C belt that I replaced at the same time.

The only roller that touches the smoth side of the belt on my car is the tension roller. which I had replaced with a Duralast unti when I did the belts. Took the belt off and sure enough, there was a tiny bit of play in that new roller.

I replaced the tensioner unit with a different brand I picked up today and it's quiet as could be. I'm going to replace this aftermarket unit too, sometime in the next few weeks. I do not trust the aftermarket any more.

Next time, I'll buy online and wait the week for the proper parts to come.

[Thoragaverung]

OK, so after about 3 days the noise came back. It WASN'T the tensioner.

So after a week of gnashing my teeth I wondered if the brand new Contitech Serpentine belt wasn't to blame. I replaced it with a Gates belt from the local parts store.

Guess what? The whole thing hasn't made a peep since. I measured the Contitech and Gates belts... the Contitech (which squeals until warm) is 1.2 mm wider than the Gates, which is silent.

So there it is. After replacing half the crap under the hood, it turned out to be a defective new belt. I didn't post about it because I didn't want to be faked out again, but it really seems to be resolved.

[FiberFast]

Replace in order until the noise stops. Belt, idler pulley, tensioner, water pump, alternator, ps pump. Wehen it come to the alternator and ps pump make sure you get the right one. Generally speaking this is usually caused by a failed bearing that provides more resistance when cold, or a failing belt.

- - - Updated - - -

Also using a contitech belt for tje last two years without a meep.

[Thoragaverung]

I went in exactly that order. Thank God I replaced the belt a second time before replacing the PS pump, which looks like an "OK" job but pretty darned messy.

[hkdboarder42]

Hows your coolant? I had a similar problem when i had a small puncture in the overflow return hose. Sprayed coolant all over the belt assembly and caused the serpentine to squeak like hell on every cold start.

[Thoragaverung]

Everything in the cooling system forward of the engine block has been replaced.

It's fixed, it was a too-wide Contitech belt.

Surprising, because I've relied on Contitech stuff for years in some pretty critical applications (like timing and balance belts on 944's and 928's). Never had any problem before.