nhs156

Curious if someone can provide an opinion here. My '10 has just 13K miles on the clock, and I've experienced the following exactly twice: both times when the car was in S5 shift mode and with DSC turned off (which I've done just twice); drive it pretty darned softly otherwise:

When launching the car twice under hard acceleration, and driving on concrete road surfaces with slight surface imperfections (vs. most asphalt roads), the car will make a metallic clanking sound as it hits a slight imperfection/tiny bump in the road, and I *think* the rear wheels spin momentarily. Sounds like hollow metal poles clanking together; being dropped on the ground. Only lasts a brief sub-second, and then disappears once I stop accelerating, but it's fairly loud. It sounds like it's coming from the rear of the car (or perhaps middle, but definitely not the front).

From what I've gathered from a brief search, I've seen some describe it as (a) guibo, (b) CSB, (c) driveshaft, (d) exhaust mounts, (e) motor or transmission mounts and (f) VANOS - don't think it's the latter; had a Z4MC with a VANOS issue and it sounded nothing like this.

Of course I have plenty of warranty left so will have the dealer take a look. But would appreciate any/all thoughts. Also, I have no earthly idea what a guibo or CSB is - so clarification would be appreciated!

Thanks.

P.S. It's not the same very quiet metallic clinking Cicada posted a vid about - that appears to happen on slow accel or coming to a stop. Only happens under hard accel with DSC off, and is far more noticeable; wouldn't need to wind down the windows to hear this one!

Hasan Shaikh

Does it happen only when you had your foot off the accelerator and you press again, or even when you had your foot on the accelerator already and just floor it from there?

If it happens when you have your foot off the accelerator and you press hard on it, its perfectly normal.

HEAT'N'COOL

This metal clank happens to me DSC off with S6 on. Never does it in S5... Happened again this weekend. Taking it to the dealer. i will let you know what I find out....

ujparise

Its your sun roof, there is a tech service bulletin, it scared the crap out of me, 200 to fix it, sound s like metal weights hitting each other!

__________________
2006 BMW M5, her name "Bella" (because my wife won't let me name any children that): SMG, loaded every option

Exterior Modifications: 3M clear bra and mirrors, Modded OEM rims

Performance Modifications: Full RPI GT Exhaust, RPI cold air intake kit, RPI Under drive pulley, JAWS Alpha-N tune

nhs156

You're absolutely correct! I realized this today, before even reading your post. Launched a couple of times with DSC off in S6 (not S5 as stated earlier) and it was clearly the sunroof. Should be fixed free as the car's still under original warranty, but appreciate the heads-up on the service bulletin. Don't suppose you have the bulletin number by any chance? Tends to expedite things with the dealer...

HEAT'N'COOL

It is for sure.. Took it out today and got on her. Man! Sound scared me. Not a natural sound at all. As described above it sounds like metal weights getting hit together. Cheers

Chris

HEAT'N'COOL

To help you out. Look at this list. It has the all the service bulletins to listed. This will help you out.


http://www.bimmerdrivers.com/forum/a...3&d=1275692951

Cheers,
Chris

nhs156

Thank you very much - very helpful!

ujparise

Glad I could help, if you are under factory warranty yes, extended, no because nothing is tech broken

stevezx900

I had the same problem! Lifted the whole car up recheck all trans cover bolts. Checked to see if anything was banging around when I hit bumps. What a headache for two weeks before I figured out it was the sunroof.