[redbeardbeer]

Hi all.

2008 E90 323i Sedan - auto.

I have a very strange sound coming from what appears to be the passenger (left side of the car as car is right hand drive) footwell or under the seat.

When I swerve the car side to side while driving, it sounds like something solid and heavy is rolling back and forth and hitting on something as it comes to a stop each time. I thought there was a perhaps a socket under the seat rolling back and forth but there isn't - and sounds heavier than this.

I have taken seat out - taken subwoofer out - can't see anything rolling around.

Is there a false/double floor to these cars? The noise is really annoying!

Cheers
Hunt

[redbeardbeer]

Ok this is embarrassing.

I found this inside the air vent that goes under the seat.

[mainbearing]

Your initial guess was absolutely correct!

[autoart]

Oh my god, the same thing was happening to me. I removed the passenger side front and rear door panels. The B pillar panel and the passenger side seat.
I just went and looked in the vent and found a metal part in the vent.
Thank you!!!

[jbellk75rt]

The only thing to be embarrassed about would be if the socket was yours. Excellent diagnosis.