Cow Bell Noise: Losing Patience

[Seattle S65B40]

I've now had my car serviced twice for this issue twice in the past 3 weeks and it's as bad as its ever been.

I've already had both rear bearings replaced and diff fluid changed. I highly doubt it is a stone/pebble trapped between the caliper and heat shield, as some have suggested. This makes more of an inconsistent tumbling sound, as my guess is that would tend to make more of a consistent sound. I really tried to drive it off tonight, but it is now doing it continuously. I have no choice but to take it back to the dealer, but was hoping to get some help diagnosing it.

Here's a video:

[mike33176]

"I gotta have more Cow Bell"

[Seattle S65B40]

Originally Posted by mike33176

"I gotta have more Cow Bell"

[Echo M3]

Originally Posted by Seattle S65B40

I've now had my car serviced twice for this issue twice in the past 3 weeks and it's as bad as its ever been.

I've already had both rear bearings replaced and diff fluid changed. I highly doubt it is a stone/pebble trapped between the caliper and heat shield, as some have suggested. This makes more of an inconsistent tumbling sound, as my guess is that would tend to make more of a consistent sound. I really tried to drive it off tonight, but it is now doing it continuously. I have no choice but to take it back to the dealer, but was hoping to get some help diagnosing it.

Here's a video:

It sounds just like the 'pebble stuck behind the heat shield' sound, which can also be described as the 'dragging tin cans under you' sound.

It stuck with me for almost a hundred miles, until one one day when it magically vanished. If you're concerned, take it to the dealer. But to me, that sounds very much like something (a pebble) is stuck in the heat shield.

[Seattle S65B40]

Originally Posted by pman10

It sounds just like the 'pebble stuck behind the heat shield' sound, which can also be described as the 'dragging tin cans under you' sound.

It stuck with me for almost a hundred miles, until one one day when it magically vanished. If you're concerned, take it to the dealer. But to me, that sounds very much like something (a pebble) is stuck in the heat shield.

I guess that is somewhat reassuring, but its pretty loud and embarrassing. Should be a quick fix I would think, but if that's what it is, it could probably happen again at any moment too.

[Echo M3]

Originally Posted by Seattle S65B40

I guess that is somewhat reassuring, but its pretty loud and embarrassing. Should be a quick fix I would think, but if that's what it is, it could probably happen again at any moment too.

The only other thing I could think of was the differential, which you've already had serviced. Have you attempted to remove your wheels and have a peek at the heat shield or around the calipers? Are you sure someone hasn't pranked you by hiding a remote speaker in your underbody?

[Mjolnir]

The exact same thing started happening to me but very intermittently. The first time it happened I took it to the dealer and of course it stopped by the time I got there. My luck being what it was, it started again by the time I got to work that morning.

Someone on here suggested doing several hard brakes at higher speeds. It actually seems to work. It still happens occasionally but braking hard seems to cure it. Give it a try.

P.s. Thanks for posting video. Now at least I know the sound I'm hearing is the same as what others are experiencing.

[jeff@autocouture]

Im pretty sure it's just the exhaust,

[elh0102]

It's the e-brake adjustment spring in the rear. Mine did the same thing, and the tech said he had seen a couple other M3 cars with the same problem. How could anyone think that is a bearing or differential sound?

[GreasyGinzo]

Originally Posted by elh0102

How could anyone think that is a bearing or differential sound?

x10 it is obviously a hollow or tin sound...nothing that a bearing or diff would make. I would guess the exhaust is touching the heatshield somewhere.

[GreasyGinzo]

Or possibly a rock or something rolling around inside the exhaust

[dmn8]

Have had this over the past 2 years a couple of times never brought the car in. Last week had to have service and it was happening again and had them look at it. They reported back the following on the service invoice:

Normal characteristic for model year vehicle. See attached bulletin #330108.

Obviously a now documented issue that they do nothing about.

3 days later and it is now gone....

[RoundTwo]

lolz MOAR COWBELL

[Jaypod]

Sounds EXACTLY like the stone/pebble trapped in the heat shield. Try pushing your heat shields away from the rotors a bit with a long screw driver. When removing the wheels, if you accidentally rest or hit your wheels against them they will bend a bit as well.

[elh0102]

Originally Posted by Jaypod

Sounds EXACTLY like the stone/pebble trapped in the heat shield. Try pushing your heat shields away from the rotors a bit with a long screw driver. When removing the wheels, if you accidentally rest or hit your wheels against them they will bend a bit as well.

Believe me, it is not, although it sounds very similar. It is the e-brake.

[RoundTwo]

i think elh0102's got it.

[Seattle S65B40]

Originally Posted by elh0102

It's the e-brake adjustment spring in the rear. Mine did the same thing, and the tech said he had seen a couple other M3 cars with the same problem. How could anyone think that is a bearing or differential sound?

Interesting. So is this something the dealership should be able to fix?

Can anyone pull up this bulletin #330108? I'm guess this bulletin relates to exhaust noise, which is considered normal i hear. Are people with aftermarket exhausts having any similar problems? That would rule that out i suppose...

[elh0102]

Originally Posted by Seattle S65B40

Interesting. So is this something the dealership should be able to fix?

Can anyone pull up this bulletin #330108? I'm guess this bulletin relates to exhaust noise, which is considered normal i hear. Are people with aftermarket exhausts having any similar problems? That would rule that out i suppose...

A competent tech can fix it. Whether your dealer has such, I can't say. And yes, there have been some exhaust-related noise that sound similar. But the e-brake's noise is very discernably and directly related to the rotation of the rotor, which you can hear. An exhaust system related noise is going to vary with the random vibration of the components involved, and temperature. To suggest either one could be differential or bearing related is really ridiculous, and makes me doubt the competent tech thing, but best of luck.

[Seattle S65B40]

Originally Posted by elh0102

A competent tech can fix it. Whether your dealer has such, I can't say. And yes, there have been some exhaust-related noise that sound similar. But the e-brake's noise is very discernably and directly related to the rotation of the rotor, which you can hear. An exhaust system related noise is going to vary with the random vibration of the components involved, and temperature. To suggest either one could be differential or bearing related is really ridiculous, and makes me doubt the competent tech thing, but best of luck.

Thanks. I will let them know. Can you confirm that "driving it off" will not make this one go away?

In fairness to the dealer, there was also an ABS light on the second time I went in, and the bearings most likely related to that. The cowbell was not reproducible at that time, so perhaps, based on my description, they thought I was referring to the common problem under SIB 330102, and therefore changed the diff fluid.

[dolby]

Mine went in today to get new rear pads and DCT update. I also told them about the same noise from the LR wheel and it possibly being an issue with the e-brake cable. I'll update if they find anything.


Dolby

[Seattle S65B40]

Originally Posted by dolby

Mine went in today to get new rear pads and DCT update. I also told them about the same noise from the LR wheel and it possibly being an issue with the e-brake cable. I'll update if they find anything.


Dolby

Thanks, that would be great.

Does anyone else agree that this is flat out embarrassing? No wonder i was getting funny looks rolling around town yesterday. A car this nice should not be making that kind of noise with less than 13,000 miles on the O/D. It's LOUD and makes the car sound like a p.o.s.

[3XTR3M3]

This thread definitely needs more cowbell