Yesterday I was out driving my 2007 M6 it was in Automatic. I was entering the highway from entrance ramp and I dove into the peddle "hard Exceleration " . I heard a bang like some hit hard under the car . When I got home I looked all around the car and under the car nothing. Anyone have any thoughts ?
Was anything different after you heard the noise? Was the engine power the same, you kept accelerating, or slowed down? Was the engine running & idling smoothly afterwards? Did it sound the same?
I didn't feel or notice anything different in the way the car drove. It's was just weird because I did not hit anything in the road.
I think I've seen posts of a bearing problem with those 10-cyl. engines, or something like that, but maybe I'm getting that mixed-up with the E92 M3 motors. If you didn't notice any difference in the engine's running/power/idling, perhaps location is relevant - perhaps hard to say with a brief one time occurrence, but was the sound noticeably from a particular part of the car? I know the engine bay's stuffed, but I'd pop the hood and use a flashlight to see as much as you can towards the underside - modern BMW engine bays are pretty well faired-in with plastic underbody panels and cladding, I think for aerodynamic purposes. If something went underhood, maybe there would be visual evidence. A loud bang from the engine area would have different implications than from the back half of the car, for instance. Mileage?
Could of been a hard downshift from the smg transmission. These can sometimes bang under hard acceleration, if your not hearing it now I would not worry about it.
I also have experience that clunk /bang in automatic under acceleration. I have have spoken to my tech and have had the car on the lift and all appears to be in order. Like charlson89 he said it is inherent to the SMG in auto for this year. As a test I used the manual (paddles) on the same road situation with no noise.
