[pileofstack]

Hey Guys, got a new noise that I've never heard before on these cars. Pretty well-versed in the N54, but this one has me stumped. Did some extensive research with absolutely no luck. Anyway, on to the issue:

Alright, so I drove my 335i through the winter and it performed flawlessly and was a blast. At 118k miles, it's the first winter it's ever seen. About 2 weeks ago it was warmer than usual in the morning and sunny (about 45°), so I drove to work with the my front windows about halfway down. It was at this point that I noticed a squealing noise rising and falling, in sync with the engine RPM's. However, as soon as the car is up to temp, the sound goes away and everything is fine and dandy.

Checked voltage at cold start and it hovers just over 14, so it can't be the alternator. The squealing doesn't change when I'm stationary and turn the wheels, so I don't think it's the PS Pump (non-active steering); which also leads me to believe that it's not associated with the accessory belt considering, when there's more resistance on the PS pump, the noise doesn't change... I could easily be wrong on this.

If its none of those things, could it be something deeper related to timing or the lubrication system? The noise is coming from the front of the engine, I just can't quite narrow it down any more than this... Any help is greatly appreciated!

FYI: I change the oil every 3k and the accessory belt system was done at 80k.

[mweisdorfer]

I would point to the belts. Especially, if this was the first winter the car has seen. Rubber tends to harden up in the cold and hence the squeal. The warm, cold, warm cold cycle does not do rubber on a car any favors. Probably need to really look at all of your pulleys and belt tensioner plus the belt itself. ECS tuning has a good deal on a kit for around $150.00.

[pileofstack]

Originally Posted by mweisdorfer

I would point to the belts. Especially, if this was the first winter the car has seen. Rubber tends to harden up in the cold and hence the squeal. The warm, cold, warm cold cycle does not do rubber on a car any favors. Probably need to really look at all of your pulleys and belt tensioner plus the belt itself. ECS tuning has a good deal on a kit for around $150.00.

Yeah, I think I'll just bite the bullet and get that again from ECS (that's what I did at 80K). It kind of makes sense to go back through considering it's been almost 40k miles +1 harsh and salty winter since I did that. It's probably safe to assume that the winter cut the life of those parts in half.

[gabylonfive]

agreed, definitely sounds belt related. ECS just got the kits back in (just ordered one) as they were backordered for a bit. good luck, hope it fixes the issue.

[Scottycs]

fix it asap! My belt squeaked 1 day and the 2nd day it shredded and wrapped itself around the alternator. A leaking oil filter housing gasket is what started my problem.

[pileofstack]

UPDATE:

I just did the Accessory belt and pulleys (local BMW dealer had the parts in stock) and the squeak remains. While I was in there, everything looked clean with no sign of fluids/oil leaking anywhere.

This leads me to believe it's something to do with the alternator, power steering pump, or the A/C compressor pulleys, as these were not included in the kit. Anyone know if one of these start to go at around 120k?

[catcher22]

I'm having this exact same problem. Squeal on cold start up which goes away completely after the car warms up.

Did anyone find a solution to this issue?

I'm thinking of replacing the tensioner pulley and belt and will report back afterwards.

[pileofstack]

Originally Posted by catcher22

I'm having this exact same problem. Squeal on cold start up which goes away completely after the car warms up.

Did anyone find a solution to this issue?

I'm thinking of replacing the tensioner pulley and belt and will report back afterwards.

SOLUTION:

It was the belt. Upon inspection, it looked fine (no cracks, etc) but it must have been warn. As soon as I replaced it all the noise went away. When I posted that I replaced the belt, I forgot that I had inspected the "newish" belt and found it to be visibly good, but that wasn't the case.

[theweebabySeamus]

Good on you for doing it. I pushed the service out and it ended up in my crankcase.

[tc535i]

Originally Posted by pileofstack

SOLUTION:

It was the belt. Upon inspection, it looked fine (no cracks, etc) but it must have been warn. As soon as I replaced it all the noise went away. When I posted that I replaced the belt, I forgot that I had inspected the "newish" belt and found it to be visibly good, but that wasn't the case.

it's more an issue of the rubber hardening and "glazing", which keeps it from getting a good grip on the pulleys. That makes it slip and squeak until it heats up and gets grabbier