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Discussion Starter #1
Did some searching on "start up squeal" and "starter squeal" and the discussions were inconclusive. I'm at about 67k miles, and sometimes I hear a squeal at start up. Not tied to cold starts, either. It's a more mechanical squeal sound, vs. just a belt screech, and seems to coincide with what I would expect the starter would experience as far as a second or more of residual engagement after the engine fires and takes over. Are these motors prone to this at this mileage? Again, didn't see a bunch of discussion on failure of the part. Maybe one PO started it like a Cracker Barrel designated driver with bad hearing. It happens in about 1 in 4-5 starts, and split between cold start, warm restart, and semi-warm restart (2/3s tach LEDs lit, or about 3-ish hours).

It looks like the starter motor is a reasonable DIY, but parts can be harder to find these days. I'd hate to do an unneccessary DIY when the CABs on the ZHP really need to be done...soon!

Thanks, folks!
 

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I want to say it's the bearing in the starter motor, but without hearing it I'm shooting in the dark. To my knowledge, starters aren't a known/prone-to-fail component w/ the E39.
 

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I have the exact same sound intermittently on mine. I do not believe it is something to worry about until it starts happening more consistently
 

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Discussion Starter #4
For distance evaluation of sound, the best I can describe is it's a very high-pitched whine/squeal that starts from engine catch, rises as the engine enters start, and drops off rapidly as the engine enters idle. It almost sounds a bit like a kid's whistle that is air current driven. And it *seems* to come from the passenger side, which drives me to the starter motor bearing or impeller. My original thought was maybe the impeller wasn't retracting fast enough, over-spinning the starter motor. But only occasionally. Which is weird.
 

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Sounds like a sticking bendix(part that engages the flywheel). When the engine starts it should slip, because the starter turns the motor at a slower speed than idle. Likely dirt or some other little issue. I would get the DIY out for starter replacement and pull the starter out.

Take it to your bench and look at the big part just behind the gear that engages the fly wheel. For lack of better term that is the one way clutch, and what is likely causing the issue. Clean it with some brake cleaner then flush it with oil and compressed air. Lube the end bearings while you have it out, check the bare wire from the solenoid to the motor clean the rest up and reinstall.

My bet you would get years of quiet service out of it after that.
 

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Sounds like a sticking bendix(part that engages the flywheel). When the engine starts it should slip, because the starter turns the motor at a slower speed than idle. Likely dirt or some other little issue. I would get the DIY out for starter replacement and pull the starter out.

Take it to your bench and look at the big part just behind the gear that engages the fly wheel. For lack of better term that is the one way clutch, and what is likely causing the issue. Clean it with some brake cleaner then flush it with oil and compressed air. Lube the end bearings while you have it out, check the bare wire from the solenoid to the motor clean the rest up and reinstall.

My bet you would get years of quiet service out of it after that.
Thank you.
 
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I had a very similar noise last year. After research here, I replaced the starter. The noise went away for some time, but came back. Ultimately my clutch, while not slipping, developed a slightly "gravelly" feel. Turns out my throwout bearing was shot. After replacement (of course I elected to replace the clutch at the same time given I was at 70K), the noise has not recurred. My shop (and the BMW L1 master mechanic the shop employs) feels the squeal was ultimately due to failure of the throwout bearing.
 

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Ac compressor bearing?
 

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Spray some lubricant on your alternator pulley. If the squeaking goes away it's most likely the bearing.

Mine is making a "sss sssss ssss" sound on idle cold start at the moment.
Pulling my hair out trying to get it sorted. I hate strange engine noises. VANOS rattle is bad enough but squeaking is just too much for me!
 

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Spray some lubricant on your alternator pulley. If the squeaking goes away it's most likely the bearing.

Mine is making a "sss sssss ssss" sound on idle cold start at the moment.
Pulling my hair out trying to get it sorted. I hate strange engine noises. VANOS rattle is bad enough but squeaking is just too much for me!
I had that "ssss sssss ssss" and waited too long. Serpentine blew up.
 
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