[asonntag]

I have a whistling/squealing sound coming from a pulley, belt or idler tensioner....I believe. Thought I'd check and see if anyone else is having a similar issue before I go replacing parts.

It's an intermittent problem that happens maybe 10% of the time. So it's pretty much impossible to have a shop diagnose.

I've heard the noise in all weather conditions, so I don't believe it has anything to do with getting wet or being cold. It's never done it from a cold start up. It seems every time I've heard the noise the engine has at least had a chance to warm up.

The noise is the loudest when sitting at a light idling or cruising at any speed. It seems when I accelerate the noise pretty much goes away.

The weird thing is if I shut the car off and immediately restart it. The noise disappears and does not come back for days or weeks.

Any ideas where to start? Or how to quickly pull over and identify the source of the noise next time I hear it?

[mlifxs]

could be belt related or....
there are noise issues related to valve cover, vanos solenoid, eccentric shaft sensor as well. I have a thread "CEL and a whistle" that may or may not be relevant. There is a recent thread in the n52 subforum regarding P0012 error msg, that might be relevant. I would browse /search that forum and the maintenance forum. If it keeps happening, have someone inspect the belt or scan the car for codes.

edit for...
link to CEL and a whistle
http://www.e90post.com/forums/showthread.php?t=691932
link to P0012 error
http://www.e90post.com/forums/showthread.php?t=719660

hopefully it's something simple like a belt or cleaning the vanos solenoids.

note your car may be recording BMW codes even without a check engine light. There is some good windows software out there ... **************.com if you want to check codes yourself. If you have a check engine light, autozone and other such places can read it for free, but they may not be able to see the BMW codes.

[mlifxs]

Originally Posted by asonntag

The noise is the loudest when sitting at a light idling or cruising at any speed. It seems when I accelerate the noise pretty much goes away.

The weird thing is if I shut the car off and immediately restart it. The noise disappears and does not come back for days or weeks.

My car did this as well.

[GoRomeo]

Most likely your belt tensioner needs to be replaced. Good luck!

[asonntag]

Originally Posted by GoRomeo

Most likely your belt tensioner needs to be replaced. Good luck!

That's what I thought the first time I heard the noise. But it doesn't make sense that when I restart the car the sound goes away. All cars I've had in the past seemed to make noise 24/7 once the belt or tensioner started to go bad.

[GoRomeo]

Originally Posted by asonntag

That's what I thought the first time I heard the noise. But it doesn't make sense that when I restart the car the sound goes away. All cars I've had in the past seemed to make noise 24/7 once the belt or tensioner started to go bad.

Ok, next step I would do is to clean the vanos solenoids. Its easy and fast. No need to buy parts yet. This way you can discard this posibility without hitting your wallet.

[ironclaw]

I'm sorry to open an old thread, but my E87 130i (2007/Manual) has just started doing this exact same thing as per asonntag's opening post.

No error codes, CEL etc.

Did anyone positively identify a fix?

[M335M'RIZED]

Had my accessory belt swapped out due to the squeaking problem and in the process my mechanic found the true cause. Oil leaking onto the belt and pulley from gaskets that have went on the oil filters. It has been about 6+ years ago my e92 was produced so it was bound to go. Check it out because if you do just the accessory belt without checking you can have oil ruin the new one. This only arouse during the colder weather for whatever reason

[trd5004]

I've been having this same "chirping" noise in my 2006 325xi. I've replaced the tensioner unit and idler pulley and I'm still getting the noise. I also put a new belt on when putting these new parts in. It only does it for roughly 10 seconds when I start the car, goes away, then comes back at lower speeds mostly when I'm not accelerating. I don't have any fault codes showing....does anyone have any advice for this? I don't want to replace all the pulleys if I don't have to but this sounds is driving me crazy!

[cybermgm23]

It's the belt tensioner, just went though this with the dealer, replaced under warranty. Apparently 1 of 2 things happen, 1) the bolt head that holds the tensioner in place shears off causing it to sit slightly ajar and thus causes the belt to "dance" or 2) the tensioner spring stretches over time and then no longer applies the correct tension and causes the belt to slip. It's a cheap part to replace. However if you let it go and the belt slips while at speed, it can get wrapped around the main crank and get sucked in through the main seal and into the timing chain causing catastrophic failure. You don't want to ignore this common issue.

[dannyjones]

Originally Posted by trd5004

I've been having this same "chirping" noise in my 2006 325xi. I've replaced the tensioner unit and idler pulley and I'm still getting the noise. I also put a new belt on when putting these new parts in. It only does it for roughly 10 seconds when I start the car, goes away, then comes back at lower speeds mostly when I'm not accelerating. I don't have any fault codes showing....does anyone have any advice for this? I don't want to replace all the pulleys if I don't have to but this sounds is driving me crazy!

That could be a bad pcv valve stuck open. Causes excessive vaccuum in the crankcase from the intake vaccuum, especially at idle or deceleration. The excessive vaccuum causes air to be sucked through the front or rear main seals making that noise. Mine currently has this problem and I'm waiting for cooler weather to replace the valve cover (integrated pcv valve on the n55)

[moneybimmer]

is it the same problem as mine for noise ?

[markv123]

I've had a chirping / high whistle sound, etc, etc and made a thread.
My solution is at the end.
This was for me though and maybe not for the recent posters here.
Good luck

http://www.e90post.com/forums/showthread.php?t=1311941

[Rod4a]

Originally Posted by moneybimmer

is it the same problem as mine for noise ?

Did you figure this out? I have the exact same issue.

[Rod4a]

Originally Posted by mlifxs

My car did this as well.

Did you figure this out? I have the same issue.

[tspv6570]

Hi all, my car has been making this high pitched chirping noise for almost a year, it seems to come from the passenger side foot well. Happens when the engine is cold, at around 2000 RPMs, the AC or fan is on, while turning left and pressing the gas. Mechanic replaced the tensioner, pulley and serpentine belt but the noise didn't go away. Any clues as to what could be causing it?

Below is a link to the voice note with the annoying sound:

https://www.dropbox.com/s/g8meuhxi8w...0copy.m4a?dl=0