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Discussion Starter · #1 ·
i have searched for this but all answers pointed to ac belt which i changed over the weekend. there is a terrible sounding screech noise that ONLY occurs on cold startups. i really hope it is the other belt, but i have a feeling it is the vanos unit with no oil pressure as i changed my oil about 2 weeks ago and this problem became more apparent. if it is the vanos is there anything to worry about other than the embarsing sound? i just ordered magnaflow cans today and will be put on with the x-pipe i have at home, so maybe this will mask the sound in the morning. :haha::haha:
 

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belts, pulleys
 

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Sticking belt tensioner?
 

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Spray WD40 or "belt conditioner" and cause the belt to slip momentarily. If no screech from cold start-up (or severely muffled), it's the belt. Otherwise, might be something nastier.
 

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Belts only screech if they are slipping on a pulley under some load. Let's face it, in order to slip a properly tensioned belt on any pulley, the suspct pulley has to have a substantial load on it.

I'd bet it is the alternator going. VANOS runs by chains IIRC.

You could use the WD40 suggestion and try each pulley one at a time.

This is something that needs attention.
 

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Discussion Starter · #6 ·
going to try the wd-40 test on the pulleys. My camaro's idler pulley exploded on me while driving one time with no prior warning, kinda sucked. alternator huh? i hope not. this sound only lasts maybe a half second, and is not that horrible typical squeely belt slip sound. i should have added this to begin with, sorry.
 

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i have the same problem as you..do weird sound like crunchin or like the engine is running w/o oil..but only last half a second and dissapear. when the engine is hot this sound is not present..hope you find out and lmk thanks
 

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Discussion Starter · #8 ·
i have the same problem as you..do weird sound like crunchin or like the engine is running w/o oil..but only last half a second and dissapear. when the engine is hot this sound is not present..hope you find out and lmk thanks
yep that's the sound, glad I am not the only person that has the problem.
help please!!ouich
 

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I don't want to say the v-word as I think it's over-used. For example:

Q: What's that weird engine noise?
A: VANOS.

Q: Why does my car hesitate like that?
A: VANOS.

Q: Why did my car flip over?
A: VANOS.

I bring this up to make sure it is a belt problem. You don't have an electronic oil pump for your VANOS, do you? This would most likely not be on a brand new M5.
 

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I have the same noise. I thought it was my alternator belt/idler pulley. my belt was toast, was missing a rib. I replaced both belts and the alt. idler pulley, but I still get the sound.
 

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Discussion Starter · #11 · (Edited)
well to answer the vanos question, i did some digging in vanos related problems. the only thing that comes close to maybe what this may be, is a recall or TSB that had to do with a revised vanos system that had the ability to get oil into the vanos system better than orginal. I'll have to look it up again and post a link.

oh and no electric pump, just stock.
 

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i really doubt that its the vanos ..i hooked the car to a Gt1 and there are no codes for vanos.i was told that this are the oil something that get discharged when cold and when you start the engine they get charged,also i dont know if my car has the vanos update..i have the EURO model with 10k miles on the odo.also the sound is more related to a crunchin than to a belt sound..its more like metal ..
 

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Discussion Starter · #13 ·
let me see if i can video it and post it on here, moving tommorow so it will have to wait to next week
 

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sticking starter motor probably
 

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Either your belt is loose/worn, or one of your accessories is about to need a new pulley bearing.

Cheapest (and good preventative maintenance) thing to do is to replace your belt. Once you get the old one off try to turn each of the pulleys by hand. Most should turn relatively easily. The one that doesn't (or makes a grinding/screeching noise) is the one you need to replace.

As for VANOS - not with that type of noise IMO.

As for starter motor, it can make that noise, but not if it also starts the car - the noise results from the teeth of the start bouncing off the teeth of the flywheel and the starter spinning without load.

d-
 

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Discussion Starter · #17 ·
i will take a belt pulley problem all day long over a vanos, alternator, starter problem. gonna check it out as soon as i finish moving tomorrow.
 
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I had a similar problem ealier this winter...

Try turning your steering wheel while the noise is present and see if this has any affect on the sound. If it does, check your power steering fluid levels. After I topped mine up, the screeching stopped for me.

Good luck.
 
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