Clunk sound from F10 M5 rear on bumps
Hi there fellow M5 F10 owners,
My car is at the service for 5 days now all broken down in parts and being very "roughly" test driven to find out a strange sound that the car had when it was stock. The sound was coming from around right (or right and left) shock absorbers when passing a speed-bump at 10 km/h. At first I thought it was the car wash stuff in the trunk, but once I cleared everything out - the annoying sound continued. It has now been 5 days that it's in the service, they've taken out whole back seat out of the car, all stitching, wiring, swapped shock absorbers and whatnot and still can't find the reason for the sound.
Whole rear of the car is taken out (like a rally car) and technicians were riding in the trunk with microphones and headphones to pinpoint the place the sound comes from. They said it's above the rear wheel somewhere but still can't find anything (5 days of ripped apart car for nothing) and the last thing they'll be trying out tomorrow is to try using regular 5 series shock absorbers and make another very rough dighole test-drive.
Got 3 questions
1) Does anyone else have this problem? Or payed attention if this "dong" sound from the rear at speed-bumps is normal in any way shape or form?
2) They've been test-driving my car on very deep and rough roads for 5 days now to help find the sound (I'm very upset about it), do you think this would shorten lifetime of components or overall well being of the car? They drove about 1 km of very bumpy holes at average speeds every 2 hours, trying different setups. Shall I lodge a complaint or do you think it's nothing to worry about for a new car?
3) I saw that they had taken out whole rear part of the car, seats were taken out and split apart (rear and lower parts of back seats were separated), the way from rear to trunk was opened for a technician to lay down and diagnose the sound, protective covers in the trunk and under the rear mirror were removed and many car's details were analyzed separately. Basically they've screwed with everything that was in the second half of the car, interior, exterior and drivetrain. They said it's nothing to worry about and that they will put everything back as it was in factory. But having seen my car at such condition has given me a feeling of buying a "broken, used and heavily exploited" car. Basically my car arrived with a flaw that required severe exploitation to identify the problem, and even then it wasn't identified and it has only 500 km on it. My question is, is it true that the dealership can never assemble parts back the way factory did? I'm considering lodging a complaint straight to BMW because I wanted a fresh car and seeing intestines and ugliness of a disassembled car gives me no peace of mind.
I'm very frustrated and upset, the forum was the only place to ask for an advice. Thanks for reading and for any recommendations.
Last edited by singularity; 04-02-2012 at 05:49 AM.