What is this noise? idle pulley squeal?

Have owned an 08 M3 Coupe for a few weeks, with 90k on the clock (~55k miles).

This squealing noise is present sometimes, other's not. It increases pitch with revs. Nothing else out of the ordinary.

I'm going to take it back to the dealership in under warranty, but any ideas of what would be? idler pulley or something more serious?

cheers !

You'll probably get more responses if you post this in the engine or general sub forum.

Yeah , this sounds like the belt or wear from the pulley axle .
No worries , it's no big deal .

m3m3mr wrote

You'll probably get more responses if you post this in the engine or general sub forum.

My bad.. I thought that sub forum was just for modification questions. Thanks.

OP, try to spray some water at one belt at the time. If it is a belt - which it sound like - it will silence for a minute and it helps you track the onf.

dnbosiris wrote

Have owned an 08 M3 Coupe for a few weeks, with 90k on the clock (~55k miles).

This squealing noise is present sometimes, other's not. It increases pitch with revs. Nothing else out of the ordinary.

I'm going to take it back to the dealership in under warranty, but any ideas of what would be? idler pulley or something more serious?

cheers !

For your car's age and mileage, the most likely cause of this scenario on an E9X M3 is a failing idler pulley. Not a big deal if you have some DIY skills. Also a good time to change your belts since it requires no additional work with this job. Check out this thread to learn more and make sure you order the correct part number based on the build date of your car (details in thread)!

Have the same sound(s)/issue from my 08 ~65k mi. Mine will sometimes go away when it warms up or is ran and sometimes it's still there when I get home from driving.

For mine, it sounds like the noises are coming from the large water pump pulley. But was thinking if I were to change the water pump or idler pulley, I might as well just do the Macht Schnell kit since it would come with 2 new belts anyway

I have the same noise what did it turn out to be?

I'd love to know if OP found out the root cause. I stopped at a Euro mechanic when I heard the noise while driving home, but unfortunately, as soon as I pulled in, it stopped. He suspected the water pump to be the cause but also wanted to replace the PS pump and all the idler pulleys anyway. But listening to it (even with a mechanic's stethoscope) I think it's the water pump making the noise.

The idler pulley is mounted very close to the water pump and a known wear item. i'd start there

I had the same noise, I too thought it was my waterpump because it sounded like it was coming from that location but I took the gamble and I replaced my idler pulley and now the noise is gone. The part was $50 and I paid someguy $100 to put it in. The old bearing was bone dry. I bet if you just repack it with grease, it would solve the noise. I saw a video of some guy that said it's common to repack a bearing. Just pry off the shield, pack with grease and cover it back up. But this is really being a cheapskate. I didn't want to risk it but it was still in perfect condition. The bearing is not suppose to free spin, it should offer some resistance because of the grease. I didn't replace my belts or the other bearings due to my budget. I plan to replace everything when I replace my waterpump, I'm going to do that when I hit 100k mark. But for $150, it was a good band aid for now. The noise was so annoying. btw, mine is an 08 with 85k on the clock.

to those who've recently posted.
My noise just disappeared one day and never came back. i'm sure it's the idler pulley and will need replacing at some point but for now it seems to have disappeared!