[gravity7]

I have a rattle from the part pictured here on my exhaust. With the engine running, if I put my finger on top of the pin in the center of this part it stops rattling. It's just loose. It rattles variably depending on the RPM, but rattles whether I've just started up or am driving. It's only audible with the window down - but it's pretty loud.

It would seem if I just shimmy something in there to secure the pin that the rattle will stop. But I don't know it's function is and don't want to cause any unnecessary damage.

Anybody know what this part is and what to do?

[mattr832]

There’s a U shaped metal spring called the flexing bow (or something like that) and it connects the actuator to the exhaust valve. The tend to break meaning the valve can no longer be controlled by the actuator. You’ll need to buy a new flexing bow. Part is maybe $15 from a dealer. You’ll also need a way to electronically move the actuator since it tends to overextend its position when the flexing bow breaks loose. There’s some videos on YouTube, but don’t force the actuator into position with a screwdriver or something. You’ll need to use something like BM3 to get the actuator to rotate.

[gravity7]

Awesome, and thanks for the help! I'm getting a service in the next month probably - should I try to do this myself or have the dealership do this? (knowing of course it'll be much more costly to have them do it)

[mattr832]

Originally Posted by gravity7

Awesome, and thanks for the help! I'm getting a service in the next month probably - should I try to do this myself or have the dealership do this? (knowing of course it'll be much more costly to have them do it)

It's not that hard to do as long as you don't mind crawling under the back of the car. If you park it somewhere with the nose pointed downhill, then you have enough space to scoot under the backside. Search the forums for "exhaust flexing bow", and you'll find the part number. Maybe $15. Read this post for a key detail when trying to install the flexing bow.

https://f87.bimmerpost.com/forums/sh....php?t=1869651

[mattr832]

If you don't want to mess with it, then I couldn't imagine a shop charging more than $150 to fix it. It might be about 15 minutes of work for someone with experience to fix it.