[michaeldch]

Hi:

This morning when I started my 335Xi, I heard this unusual 'chirping' sound coming (apparently) from the front right side of the engine.
I think it sounds like an accessory belt - perhaps a bad tensioner?
Can anyone shed light on what this is?

Car has 50k miles on it, mechanically perfect until now...

Thanks,
Michael

[E90_boostjunky]

ask sara.

[michaeldch]

Anybody?

In the meantime, I removed the serpentine belt - it is in great condition. The bearings in the tensioner are a little worn - but not terribly so. Both left and right deflection pulleys are in OK condition - maybe a little less worn than the tensioner pulleys. I cannot detect any issues with the alternator, PS pump, AC compressor.
My plan is to replace the 4 'routine maintenance' parts (belt, tensioner, both deflection pulleys) and see if the issue is resolved.
FYI, there is no evidence of the powersteering pump pulley having collided with the sub frame.

[michaeldch]

Originally Posted by michaeldch

... replace the 4 'routine maintenance' parts (belt, tensioner, both deflection pulleys) and see if the issue is resolved....

This resolved the issue entirely - engine sounds so much smoother.
Total cost was ~$280 for the parts and shipping and it took about 2 hours for removal and reinstallation.
Hope this helps someone else... my 335xi now has 50k miles.

[BMV///M3]

I have had the same issue for a few months. Under warrenty and been to the dealer 3x, still not resolved. First time was the belt tensioner, 2nd time deflection pulley, they also found oil cooler gasket leaking and replaced the guide roller for the alternator drive belt. BUT its still chirping at a cold start. Once the car warms up it goes away. I have to drop the car off in the evenings and pick up a loaner because the problem can only be duplicated on a cold start for the techs.

Drives me bonkers. I'm going to let them know what you've done here to fix your problem. Thanks.

ps. just looked at your vid. my chirping is at a much faster pace. hmmm...

[psmitty95]

Does this sound like it could be the same issue?

http://www.e90post.com/forums/showthread.php?t=760590

Haven't noticed it for a while so kind of ignored it but if it comes back i'd love to know how to fix it

[BMV///M3]

No mine doesn't last past the cold start and doesn't change when you rev.

[michaeldch]

Originally Posted by BV335

ps. just looked at your vid. my chirping is at a much faster pace. hmmm...

In my case, the pace of chirping was determined by engine speed, so increasing engine speed caused the pace to increase. I think its also possible that if one of the smaller pulleys (such as the alternator) is the one causing the squeak, the pace will sound faster, even given the same engine speed (because the pulley is turning faster).
In the video, my car is running at warm-idle speeds - ~600rpms IIRC.

Lastly, it seems silly that the dealer is replacing components of the accessory belt drive system apparently one at a time. My thinking is that wear in one component indicates the likelihood that a related part is faulty - this is why I chose to replace all the routine maintenance parts at the same time.

[psmitty95]

Originally Posted by michaeldch

In my case, the pace of chirping was determined by engine speed, so increasing engine speed caused the pace to increase. I think its also possible that if one of the smaller pulleys (such as the alternator) is the one causing the squeak, the pace will sound faster, even given the same engine speed (because the pulley is turning faster).
In the video, my car is running at warm-idle speeds - ~600rpms IIRC.

Lastly, it seems silly that the dealer is replacing components of the accessory belt drive system apparently one at a time. My thinking is that wear in one component indicates the likelihood that a related part is faulty - this is why I chose to replace all the routine maintenance parts at the same time.

So was your similar to the sound I posted above? Mine would increase in sound to about 1200 rpm then it would go away. No issues on WOT or any loss of power, just the noise slightly at idle and increasing to about 1200.

[BMV///M3]

Originally Posted by michaeldch

In my case, the pace of chirping was determined by engine speed, so increasing engine speed caused the pace to increase. I think its also possible that if one of the smaller pulleys (such as the alternator) is the one causing the squeak, the pace will sound faster, even given the same engine speed (because the pulley is turning faster).
In the video, my car is running at warm-idle speeds - ~600rpms IIRC.

Lastly, it seems silly that the dealer is replacing components of the accessory belt drive system apparently one at a time. My thinking is that wear in one component indicates the likelihood that a related part is faulty - this is why I chose to replace all the routine maintenance parts at the same time.

Update, dealer had my car a few days, they ordered a new A/C compressor that they are going to install next week.

On the bright side, I've gotten all new maint parts on my vehicle during the factory warranty, plus I've been able to save miles on my car with it at the dealer and test the new f30. Though I like my 335 much much more.