[p30amg08]

hey guys. sometimes when I cold start. exhaust makes a rattling sound like a coin in the MPE. any idea?

[otay]

I don't have MPE, but do occasionally get rattling on startup . Seems to be temperature related...happens more when it's cold out. Could be a couple things...maybe the flap not seated all the way sometimes?

More detail on when/how it occurs would help.

[p30amg08]

Originally Posted by otay

I don't have MPE, but do occasionally get rattling on startup . Seems to be temperature related...happens more when it's cold out. Could be a couple things...maybe the flap not seated all the way sometimes?

More detail on when/how it occurs would help.

I think it might be flap. I am in TX so still hot here. car always parked in garage. only used 2 or 3 times a week. when i flip yo sport mode. the sounds goes down but not completely away. once the RPMs go down to normal after cold start sound goes away

[sandwi54]

Check your muffler for cracks near the weld. MPE has a history of developing cracks.

[Framamind]

Originally Posted by p30amg08

I think it might be flap. I am in TX so still hot here. car always parked in garage. only used 2 or 3 times a week. when i flip yo sport mode. the sounds goes down but not completely away. once the RPMs go down to normal after cold start sound goes away

I just had this fixed on my MPE last week. It's probably the fixing bow spring--which is located between the valve actuator and the flap, outside the pipe..My spring was broken, hence the "rattling change" sound from the exhaust. At that point the flap is loose and has no tension to keep it either open or closed.

Check out this thread, there's a good image of what the fixing bow looks like. It's an $8 part:

https://f30.bimmerpost.com/forums/sh...t=exhaust+flap