[Newfeebullet]

I have a rattle or ticking coming from what appears to be under my air filter. I just replaced the belt and tensioner as the tensioner was wobbling pretty bad and in tune with the noise so thought that was it, but it's not. I can feel the vibration or rattle on the fuel rail and a little bit of transfer to the oil filter, nothing on the engine. It's there at idle speed after the car has been running for approximately 15 seconds then it's constant. There's no rhythm as suck to the knocking almost like there's a loose part vibrating. There is a little bit of wobble in the new tensioner that matches to knocking sound as well, but the bulk of the vibration is belt in the fuel rail.
Thanks for the help

2011 535i gt xdrive

[95blkmax]

Cant really help you without having the car in front if us. I can suggest you get yourself mechanic stethoscope and use it to probe around the engine in the areas you think the noise sounds strongest in order to narrow it down.

It is normal for the belt tensioner to vibrate a little. On these engines even a brand new one will have a little vibration... but it should not be wobbling- that would imply a bad bearing internal to the tensioner pulley.

Do you have any trouble codes? Did you just buy this car and it had it since purchased or did it just begin doing it? These engines also have direct injection, and those injectors make a pretty loud ticking noise that is completely normal.

Hope that helps somewhat

[Newfeebullet]

Originally Posted by 95blkmax

Cant really help you without having the car in front if us. I can suggest you get yourself mechanic stethoscope and use it to probe around the engine in the areas you think the noise sounds strongest in order to narrow it down.

It is normal for the belt tensioner to vibrate a little. On these engines even a brand new one will have a little vibration... but it should not be wobbling- that would imply a bad bearing internal to the tensioner pulley.

Do you have any trouble codes? Did you just buy this car and it had it since purchased or did it just begin doing it? These engines also have direct injection, and those injectors make a pretty loud ticking noise that is completely normal.

Hope that helps somewhat

I've had the car for awhile, the noise is new. It's not the injectors ticking that I know is normal and is present. This is a completely different sound. The fuel rail itself is vibrating where it comes up from under the air filter next to the alternator. I'll take the air filter off tonight and try and get a better look in there. No trouble codes

[Newfeebullet]

Originally Posted by Newfeebullet

I've had the car for awhile, the noise is new. It's not the injectors ticking that I know is normal and is present. This is a completely different sound. The fuel rail itself is vibrating where it comes up from under the air filter next to the alternator. I'll take the air filter off tonight and try and get a better look in there. No trouble codes

Okay, update for anyone else following along…..good news/potential not so great news.
Took the belt off sound is gone so my engine is in the clear, but now how do I figure out which accessory pulley is the culprit?

Update #2 I found one of my idler pulleys isn't spinning free fingers crossed that's all it is. Note to self just change the idler pulley's when the tensioner is changed….lesson learned.

Although I'm doing this myself I do have a mechanic friend who's convinced it's my alternator out of align but there's no adjusting the pulley for this alternator and its from bmw direct and the sound wasn't coming from the alternator. BMW says there is no adjustable option for my engine. Was close to the alternator but the upper idler pulley fits the symptoms and location.

I'll let you guys know for anyone else that stumbles on this.

[Newfeebullet]

Originally Posted by Newfeebullet

Okay, update for anyone else following along…..good news/potential not so great news.
Took the belt off sound is gone so my engine is in the clear, but now how do I figure out which accessory pulley is the culprit?

Update #2 I found one of my idler pulleys isn't spinning free fingers crossed that's all it is. Note to self just change the idler pulley's when the tensioner is changed….lesson learned.

Although I'm doing this myself I do have a mechanic friend who's convinced it's my alternator out of align but there's no adjusting the pulley for this alternator and its from bmw direct and the sound wasn't coming from the alternator. BMW says there is no adjustable option for my engine. Was close to the alternator but the upper idler pulley fits the symptoms and location.

I'll let you guys know for anyone else that stumbles on this.

The upper and lower idler pulleys (deflection pulleys) were bad but NOT the problem. Just providing an update for anyone else that might come across similar issues.
I checked all of my pulleys all seems good until….the harmonic balancer. It was improperly torqued and the bolts had come loose and allowed for movement.

For anyone unsure what the harmonic balancer sounds like when it goes bad it sounds exactly like an inner engine issue with metal clicking. Quick easy test to see if it's engine related is as I said earlier, take your belt off and let the car run.

Car is running perfectly now. Hopefully some of the info helps someone else.

Take care guys