[al2fast]

Hello, searched the forum and the internet and cannot seem to find a match for this sound. Sounds like it's coming from the alternator/oil filter area. Only happens at low rpms, like coming off of idle. Giving it light throttle makes the sound more apparent, but if you stab the throttle you can hear it for a split second.

Now that the weather is nice and the windows are down it does it every time you take off. Now its got 106k and no warranty, a 2011. Does not make the noise at higher RPM's and doesn't seem to modulate with engine RPM. As you can see it happens at idle so it's not some suspension component or brakes. I could swear it is something loose that is rattling, but I haven't done much other than change the oil, filters, brakes, & plugs on this car. None of those were done recently.

Here is a quick video I took where you can hear the noise, almost sounds like you are welding:

Thanks for any input you have. I could swear it was coming from in front of the oil filter and not the alternator when I went to that side of the engine. However, in front of the oil filter there is that heat exchanger thing and I found a diagram online and doesn't appear there are any moving parts in there.

Joe

[combatbmw]

Damn that doesn't sound to good. Hope someone can help you find the answer.

[badblack550xi]

probably the alternator

[al2fast]

Originally Posted by badblack550xi

probably the alternator

Thanks, I sure hope so, definitely sounds like its coming from the top front corner by the alternator, just cannot pinpoint it.

However those suckers are not cheap. $600+ for a remanufactured one at ECS!

[al2fast]

I couldn't figure it out, took it in to the local shop and its just the tensioner pulley, WHEW! Having them throw on a new belt too while its apart, so with a new belt it will be a sub $300 total repair bill which is a pleasant surprise!

[lsturbointeg]

Originally Posted by al2fast

I couldn't figure it out, took it in to the local shop and its just the tensioner pulley, WHEW! Having them throw on a new belt too while its apart, so with a new belt it will be a sub $300 total repair bill which is a pleasant surprise!

Wait...So no more noise after replacing the belt? Sweet! To me it sounded like the alternator was going out? Thankfully it was something simple!

[al2fast]

Originally Posted by lsturbointeg

Wait...So no more noise after replacing the belt? Sweet! To me it sounded like the alternator was going out? Thankfully it was something simple!

It was diagnosed by the shop as the tensioner pulley itself making the noise. $134 part they say they can only get from BMW and they said a new belt was $52 so I ordered one of those 2. They quoted me $60 in labor to do it so I said go right ahead. Part won't be in until later this week so the noise won't be fixed until next Tuesday. Will obviously verify at that point, but I have had really good luck with this place so far!

[lsturbointeg]

Originally Posted by al2fast

It was diagnosed by the shop as the tensioner pulley itself making the noise. $134 part they say they can only get from BMW and they said a new belt was $52 so I ordered one of those 2. They quoted me $60 in labor to do it so I said go right ahead. Part won't be in until later this week so the noise won't be fixed until next Tuesday. Will obviously verify at that point, but I have had really good luck with this place so far!

Cool...Definitely let us know if the sound goes away after the work.

[Vihang Limaye]

I have almost the same noise in my 523i 2010-2011 model.

Dealer says it might be timing chain,idler pulley,tensioner and belt or DME and coils. He wants to replace all!

Let me also add that my vehicle was sent for the VANOS bolts replacement on their recalling. After that I hardly drove a 1000Kms

Any solution got?