[Mike @ SSR Performance]

We have all heard horror stories about belts slipping and getting sucked into the the N54 motors, which can cause SERIOUS damage to the timing chain. But how seriously do you all take it?








Well we hope to enlighten you, and to make you aware that this is a serious issue that should not be neglected.

We have seen this happen numerous times and want to share with you all!

Sometimes we get customers who neglect a leaking oil filter housing gasket, oil cooler gasket, or worn down belt tensioner.

All three of the things we have listed above may potentially cause your belt to slip off the pulleys, causing it to get sucked up behind the crankshaft pulley. Which may damage your engine.

Oil dripping onto your belt will cause the belt to slip under load or even start up. With this happening, the belt will have the possibility of slipping aside.

With a weak tensioner, your belt may start jumping around. Not applying enough tension to your belt and may also cause your belt to slip.

We will share this customers experience with you all, to hope that you may take it into consideration when you see oil leaking onto your belt.


This E92 335i customer has 113,483 miles on his car. The cause of this belt from slipping was due to the belt tensioner. It is suggested to inspect your belt tensioner from time to time.

We will inspect the car further to see if there are any damages to the crank, crank seal area, and drop the engine oil pan to inspect the timing chain for any damages

Leaking OFHG/OCG/VC, tensioner, motor mounts, power steering pulley, sub frame contact, etc. can all cause this...to all the n00bs out there, welcome to the wonderful world of N54 ownership!!

[Delta0311]

Hit 70k on my 335 and replaced my pullies and belt last week. Not taking any chances.

[nikitino25]

What are you looking for when you inspect the tensioner?

[007_e350]

Inspect the power steering pulley for damage , it sits so low that it hits the subframe and eventually breaks the belt, red neck solution is to grind the subframe little bit to make clearance, I heard there's revised subframe out there also,

[arhoads335i]

Oh we love the N54! I addressed my OFHG the day I bought it, then put 335is mounts in. I havn't looked at the tensioner, is it like other cars where it will make a squeak if its humid out when its going bad?

[AlpineBoost]

^ Same here, replaced OFHG and upgraded to is mounts. I plan on replacing the pulleys and belt in about 2,000 miles at 100k.

[techwhiz]

Replaced belts and pulleys a few months ago.
Cheap insurance.

[m3rxn]

Thanks bro for heads up!

[tylerboland01]

I'm about too motor mounts and front control arms, guess I'll do the belt and pulleys while I'm in there.

[twinship]

Has it been confirmed that the IS motor mounts are the fix for the pulley contacting the subframe?

Has anyone measured the IS mounts and the non-IS mounts, or photographed them side by side?

[nikitino25]

Originally Posted by twinship

Has it been confirmed that the IS motor mounts are the fix for the pulley contacting the subframe?

Has anyone measured the IS mounts and the non-IS mounts, or photographed them side by side?

Or the 034 Motorsport mounts for that matter?

https://www.ecstuning.com/b-034motor...SABEgJEBfD_BwE

[mxchris727]

Has anyone made a notch in the sub frame where the pulley hits? That would solve the problem once and for all.

[Mike @ SSR Performance]

Just an update on this thread! This customers engine was destroyed from the belt. After this post, we had attempted to remove the belt that got inside the crank seal. About 2 feet of belt came out and then it was jammed in there. We had removed the crank seal to save the time of dropping the oil pan. After inspecting it, the belt had jammed itself inside the timing chain and without a doubt, cause timing to be off. This customer had drove about 5 miles after the belt ripped.



As for the power steering pulley, this is also another common issue. Usually, is caused by weak motor mounts. Over time, the motor mounts start to stretch and weaken the polyurethane inside. Which will allow the engine to move much more and at the same time, have the engine sit lower.

The best way to inspect your tensioner is to turn on the engine and take a look at it's movement. Tensioners usually only move about 5-10mm. Anything more than that is considered excessive and should be considered replacing. As under load, it will have much more movement

[Chris@VargasTurboTech]

Good post! Significant concern and easy to check for! Blow it up from too much power, not from stupid tensioner issues!!!!

Chris

[Mike @ SSR Performance]

Originally Posted by Chris@VargasTurboTech

Good post! Significant concern and easy to check for! Blow it up from too much power, not from stupid tensioner issues!!!!

Chris

Great additional information that passed our minds. Higher power does also add to this concern. As the increased speed of crankshaft revolution does also cause belts to slip!