I Like Soup

Howdy All...at the end of May I had a crankshaft pulley/ECU tune installed on my '03 E55 (~31K miles). This was the first "performance" mod I have had done and I was quite excited. I did notice a squeal from the engine bay and figured it was the new belt that I needed for the larger pulley. Well, here it is in the middle of July and the squeal is there and all the time. I thought it went away after warming up, but this isn't the case. A friend of mine and I were under the hood and noted that the sound isn't the belt, it sounds like it is coming from the supercharger pulley. I can hear it while driving and it drives me nuts (not to mention, I wonder if something is slowly but surely being degraded).

Has anyone had this experience? Any suggestions what it may be and why? What to do to fix it? I've asked the installer several times with no response, so I'm forced to come to my mbworld brethren...thanks!

DFW01E55

Could be the bearing on the pulley tensioner. A tech should be able to diagnose with 30 seconds of listening.

Jakpro1

Couple of questions.

Can you 100% confirm it's supercharger pulley?

Just wondering if it's the tensioner pulley just to the left.

MUUUUCH cheaper pulley than a 1200$ clutch pack.

Would check that and also worth swapping the belt out for a new one.

Does anything make it go away??

Last, what belt number you running (can usually see it come around with a few cranks and a flashlight) and what type of crank pulley are you using.

Will help us to diagnose.

If you are having massive belt slip or a bad supercharger pulley, you are gonna be blown away how much difference the fix makes.

Vadim @ FD

Could be several possibilties:

- Main sc belt tensioner
- Main accessories belt tensioner
- Supercharger clutch bearing

Will you be in SoCal any time soon?

I Like Soup

Thanks guys. I'll have to verify the location of the squeal. I'm in San Francisco until tomorrow evening so can take another look when I get home as I'm going off memory from last week.

I didn't have the engine cover off, so I guess it could be the belt tensioner (I thought the noise was on the snout of the supercharger, but maybe I'm mistaken? )

The belt is only a couple of thousand miles old. My friend did note the belt looked glazed on the top (belt slippage?).

Nothing makes it go away. It is pretty obvious at start up...after warm up it isn't near as noticeable...but under way I can most definitely hear it.

Vadim, I don't foresee being in SoCal anytime soon, unfortunately. With my territory change, it would be a personal drive out there this time. I'm hoping it doesn't take VRP expertise to sort this out.

bfnnrgn

Try turning the belt around so it goes the other way. If it has an effect on the sound then you're looking at a belt.

chiromikey

my idler pulley just went out and this sounds just like your problem. very minor squeal and the back side of the belt will look glazed. take it to chris and have him put his stethoscope in there and have a listen.

psk145

I've got the same issue. Had my clutch replaced and it's still there. So it's gotta be one of the pulleys (I hope)

TopGun32

by the way gents..

don't buy a clutch pulley just because the bearings went bad.

Bearings range from $18 to $40 bucks. Really simple to install.

search the C32 forums for clutch bearing replacement.

Idler pulley or SC clutch bearings.. not the crank or anything to do with your mods.

just part of wear and tear.

I Like Soup

Well, Chris has been out (what, vacation?) so his Dad took a gander. He noted my tensioner was flopping around and thought the spring was probably going and that could cause the squeal under load. He also noted, "hey, your pulley is wobbling". Anyway, I go to NYC tomorrow at oh dark thirty and get back Sunday afternoon. I'll probably order a new tensioner and check to ensure the belt is correct (Chris' Dad's suggestion) and go from there. Still drives me nuts!