[AWSAWS]

Hi guys,
I have a noisy serpentine belt. This morning I did the trick where pouring a bit of water on it made it silent.
I assume I need to replace the belt. The car is a N54 335i.

I'm just wondering. Do I need to replace the belt or can I just decide to live with the noise for now? Do I basically check the belt for cracks, and if there are none then it's ok to leave it for now?

What are the implications if it snaps?

Thanks

[robthewrench]

It is unlikely that the belt is making the noise. More likely is that you have a pulley making the noise.

Your best next step is to try and identify which part of the accessory pulley is making the noise. The most common issue on the n54 / n55 is usually the tensioner. Many owners on this forum replace the tensioner and belt between 60-90K miles. You can find a kit to do this on ECS and other websites.

You should address this quickly. On the N54 and N55 if the belt starts to track off the pulleys the belt will start to shred and then these slivers are pulled behind the timing cover and get into the oiling system. This is typically catastrophic and can destroy the engine by clogging the oiling system.

If the belt just breaks and does not shred, you will immediately lose electrical power and steering boost. You will not be able to drive the car for any significant distance once this happens.

[BashShah]

I say why wait for a catastrophic failure which would potentially be looking for a new engine.

Just replace the following:
Belt, tensioner and both upper and lower pulleys.
Here is my DIY on N54 engines:
http://www.e90post.com/forums/showthread.php?t=1075854

Also: to find the cause of the squeak.
Is the front of your engine baked with oil residue and dirt?
If so, you have a leak in OFHG which is trailing onto the pulleys and crank pulley. And belt maybe.

In my DIY, there is a cost of parts listed.... not that expensive.
Good luck.

[ecko04]

While you may have a noisy belt, in all likelihood that’s a byproduct of a leaky OFHG (oil filter housing gasket). There’s a chance that you wouldn’t notice your oil levels going low nor any oil underneath your car because, like DarkNemesis stated, most of the leak made its way to the pulleys, destroying the pulley bearings and potentially getting on the belt thereby creating the noisy belt.

If you haven’t replaced that pesky gasket go ahead and do so while you’re doing the pulleys and belt, otherwise the problem will repeat itself if the primary issue is the oil filter housing gasket to begin with.

[AWSAWS]

Thank you guys. I will take a look and see if any of the above stick out as a problem.
I've ordered the belt itself but I wont replace it until I'm sure the pulleys or oil filter housing etc are not a problem.
The belt was not noisy this morning. Only seemed to be noisy on yesterdays cold start.

[AWSAWS]

Originally Posted by DarkNemesis

I say why wait for a catastrophic failure which would potentially be looking for a new engine.

Just replace the following:
Belt, tensioner and both upper and lower pulleys.
Here is my DIY on N54 engines:
http://www.e90post.com/forums/showthread.php?t=1075854

Also: to find the cause of the squeak.
Is the front of your engine baked with oil residue and dirt?
If so, you have a leak in OFHG which is trailing onto the pulleys and crank pulley. And belt maybe.

In my DIY, there is a cost of parts listed.... not that expensive.
Good luck.

Awesome DIY DarkNemesis, if I don't do this myself then at least I can give this to my mechanic. Thank you

[ecko04]

Originally Posted by AWSAWS

Awesome DIY DarkNemesis, if I don't do this myself then at least I can give this to my mechanic. Thank you

Most definitely!

Had I frequented the forum I would’ve addressed mine as part of routine maintenance.

Instead, I’m picking it up from the BMW dealer after a $4100+ repair of the thrust bushings (another component known to wear), oil filter housing gasket, oil pan gasket, misfire from cylinder 5 caused by a defective coil pack, faulty intake air temp sensor, faulty mass airflow sensor and replacement of the 2 pulleys and belt due to oil contamination from the gasket leak.

At least I got the airbag recall taken care of.

Luckily I had a warranty so my out of pocket expenses are $505 but it could’ve spelled disaster. I was in the dealer and I overheard repair costs on other vehicles of $6000, $5000 and $7000 to other customers where my heart just skipped a beat each time. Apparently these very costly repairs are more common than I’d like to hear.

And yes, about 60-65% of the cost was labor.

[GoRomeo]

Originally Posted by DarkNemesis

I say why wait for a catastrophic failure which would potentially be looking for a new engine.

Just replace the following:
Belt, tensioner and both upper and lower pulleys.
Here is my DIY on N54 engines:
http://www.e90post.com/forums/showthread.php?t=1075854

Also: to find the cause of the squeak.
Is the front of your engine baked with oil residue and dirt?
If so, you have a leak in OFHG which is trailing onto the pulleys and crank pulley. And belt maybe.

In my DIY, there is a cost of parts listed.... not that expensive.
Good luck.

This!