[Shotputted]

Originally Posted by bjt135psu

Found this post and I need some advice. I purchased my '11 335i about 2 months ago and have been fighting the belt squealing most of my ownership. Below is what I have done or experienced in order.

Noticed squealing
Belt Replaced - squealing stopped
Few weeks later - starting squealing again
Replaced both deflection pullys and belt tensionor - squealing continued
Completed water test and squealing paused
Belt Replaced - squealing stopped
Few weeks later - squealing started again
Identified coolant leak and replaced vent line (coolant leaked over belts; cleaned engine bay)

Squealing still continues as I start the car. It's not as loud as or as constant as it was before the tensionor, belt and pulleys were replaced. I've tried turning off the AC and the squealing persists.

What next?

Are you sure you don't have any oil leaks? If your OFHG and/or VCG have never been replaced they are probably leaking oil on the belt. That's what caused mine to squeak. I replaced the belt and the gaskets at the same time and it never squeaked again.

[bjt135psu]

Originally Posted by delmarco

Check Power Steering Levels!
I 'think' I am having the same issue as you and was told that could be a cause.

when you rev your engine, does the volume and consistency of the squealing/squeaking change?

[bjt135psu]

Originally Posted by Shotputted

Are you sure you don't have any oil leaks? If your OFHG and/or VCG have never been replaced they are probably leaking oil on the belt. That's what caused mine to squeak. I replaced the belt and the gaskets at the same time and it never squeaked again.

how many miles were on your car when you noticed the failure? i have just over 87k and haven't noticed anything specific but i'll take a look.

[Shotputted]

Originally Posted by bjt135psu

how many miles were on your car when you noticed the failure? i have just over 87k and haven't noticed anything specific but i'll take a look.

Gaskets were both leaking at 60,000 miles in my old car. My new car already had them both replaced under warranty so they leaked by 50,000. Both cars 2011 335i. Belt would be fine to around 100k miles if it weren't for the oil leaks.

[Mean E92]

I had the same issue! It was my OFHG leaking on my belt and pulleys. I left it to squeak for too long and it made the belt slip off and go inside my oil pan which ruined my engine. About 10k$ later I have a used engine installed in my car. Don't waste any time because you might loose your engine. Send your car to a dealer or a trusted indy who can identify what is leaking on your belt and pulleys. The oil makes the bearings on the pulley(s) bad and ruins the quality of your belt. Don't wait to long to figure this out!

[bjt135psu]

thanks - i'll do that this weekend. For $70 and my time i'd rather try this on my own.

i just installed new belt, pulleys and tensioners a few weeks ago, do you think those will be fine? it's mostly been sitting b/c of the coolant leak so they shouldn't have had that much exposure.

[lwgrenier]

Does anyone know where a DIY for the belt and tensioners is located?
THanks.

[CTinline-six]

Originally Posted by lwgrenier

Does anyone know where a DIY for the belt and tensioners is located?
THanks.

There are a few videos on Youtube I saw for a DIY on this.

[kievlanine@gmail.com]

I am having similar issues, I have replaced all belts, due to an oil leak from the oil filter housing gasket.
The squeak went away for a very short while, and returned more or less the same.
I couple of people suggested the crank pulley, and the timing chain while I am at it.
How hard is it to do the timing chain? Lift highly recommended?

[jan31]

Originally Posted by bjt135psu

Found this post and I need some advice. I purchased my '11 335i about 2 months ago and have been fighting the belt squealing most of my ownership. Below is what I have done or experienced in order.

Noticed squealing
Belt Replaced - squealing stopped
Few weeks later - starting squealing again
Replaced both deflection pullys and belt tensionor - squealing continued
Completed water test and squealing paused
Belt Replaced - squealing stopped
Few weeks later - squealing started again
Identified coolant leak and replaced vent line (coolant leaked over belts; cleaned engine bay)

Squealing still continues as I start the car. It's not as loud as or as constant as it was before the tensionor, belt and pulleys were replaced. I've tried turning off the AC and the squealing persists.

What next?

I’m going thru the same, how did you solved this?

[kievlanine@gmail.com]

Ok so its seems like enough people have this issue And i am pretty sure its the crank hub, if you dont have or had oil leaks as the culprit, and changed all of your pulleys correctly, its the crank hub that goes.
Timing chain should be ok, unless the timing jumped which is not related but can happen simultaneously, coincidently.

[Tallicia]

The N55 with power steering pump on oil pan seem quite likely to have a serious issue that develops over time. The oil pan mount location for power steering pump bending out of alignment causing serpentine belt failure.

The squeal will get worse and you might only get 1000 miles out of a serpentine belt.

I've replaced the crank hub/harmonic balancer, alternator, all pulleys, tensioner, and power steering pump, multiple times. The belt doesn't line up perfectly centered on the lower pulley directly in the center while it does on the 2 on the tensioner and the 75mm upper pulley. Using both N54 and N55 power steering pulleys to adjust the offset to see if it makes any difference has not helped keep serpentine belts from making horrible noises. It's like it is twisted as well as offset.

It looks like the oil pan being twisted by having bad work done at a dealership/lifted by jack/wood on oil pan, has left cracks seen on the inside of the oil pan where the 3 PS pump bracket bolts mount up. Removing the subframe to remove the oil pan to find this out is a huge PITA and massive frustration. If motor mounts get old/worn/fail, and the PS pump bumps the subframe, it's knocking the oil pan to power steering mount out of alignment possibly as well.

I'll be replacing the oil pan soon to see if things line up again.

A designs where the engine has an accessory mounted on the oil pan that leads to serpentine belt ingestion and motor failure has class action lawsuit smells.