[seadan]

I have a 2013 X3 2.8i, and the exhaust recently started rattling loudly on idle. Is this the exhaust flap/baffle/valve? All major exhaust components appear tight.

What's the best fix to resolve this noise?

Video of the noise:
https://photos.smugmug.com/photos/i-...rXS3s-1280.mp4

[383vett]

Have to put it on a lift or crawl underneath to isolate the noise.

[seadan]

After some further investigation, it looks like the issue is with the vacuum activated exhaust flap. Very similar to what's shown in this video:

Unplugging that component from the trunk resolves the rattle. That seems to be a resolution from the existing threads I found on this -- but I was hoping for a proper (DIY) fix/repair. Anyone have experience with this or tips on how to test the system to find the fault? If it's been documented before i seem to be coming up short in my searches...

[thenew3]

My wife's 2016 has had this exhaust rattle issue since new. But it only happens on cold start. Goes away after a couple of minutes. Dealer couldn't find cause after a couple visits. So wife just decide to live with it.

[F25_x3]

I just zipped tied mine to always open. I thought they would melt but they are still there a few months later

[r0bert0e]

I am having this same exact issue and will be following this thread. Please let me know if you have any luck.

[seadan]

Originally Posted by r0bert0e

I am having this same exact issue and will be following this thread. Please let me know if you have any luck.

Seems like this is a common one, but no real solution other than replacing the exhaust. I spoke with my shop foreman about this, and he actually recommended just capping the vacuum line (see "bmw golf tee mod") and being done with it. According to him the flapper's only use is in noise reduction to meet some EU city noise ordinances...I can't vouch for that but there's much discussion on this mod online.

If anyone does know of a more proper fix that doesn't require replacing the exhaust, I'm all ears!