A bee loose in my car??!!

[Barney Paull-Edwards]

Over a few months a noise has appeared in my car. I didnt notice it initially as Pink Ffloyd tends to drown everything but it was noticed by passengers, if I had a rubber mounted external pump, it would sound like the pump was touching the body, varies slightly with revs at rest, seems to be coming from the rear of car. Nothing is touching on the suspension, exhaust off and re-hung,any lateral thinking ideas?? Whole drive-train has been off for time-limited maintenance and made no difference.

[whiskychaser]

I'm thinking heat shield - the one over the steering box in particular. Or does it have a dual mass flywheel? From Luk's fault finding handbook:
'There are various causes of humming noise, for example resonance in the power train or imbalance of the DMF exceeding admissible limits. A DMF can be severely imbalanced, if e.g. the balance weights on the back side are missing, or the plain bearing is defective. Whether imbalance is the root cause of humming noise can be determined quite simply. While stationary increase the speed of the engine. If vibration increases
as engine speeds go up, the DMF is defective. Here, too, it is helpful to compare the vehicle to another car with an identical or similar engine version'

[Barney Paull-Edwards]

Thanks, good idea, will look at heat shield. Not sure if M5`s have DMF but mine does`nt,the flywheel is a gorgeous drilled, polished lump that weighs less than the Paddle plate clutch just fitted which was ,not a good idea even if it lasts for ages as it is heavy as hell and rattles like my ex-wife .Am about to replace all engine/gearbox mounts in case that is problem, will keep forum posted in case thats the answer, no, not polybush,BMW spend a fortune on R&D so why waste the money on nylon?!

[RobPatt]

what's a DMF?

[632 Regal]

what's a DMF?

Dual mass flywheel.

[genphreak]

Dual mass flywheel.

DCC: Detached Catalyst Cover

or LFHS: Loose Floorpan Heat Shielding

[Barney Paull-Edwards]

Found it!! When delivered my car had Reiger Shocks fitted with remote reservoirs. The self- levelling rear shocks were deleted BUT the sensor on the rear ARB was not. Every time the car went over a bump the pump kicked in, or when the boot was full. Disconnected the arm and pulled the lever forward, ty-wrapped it and peace and quiet again..

[genphreak]

... the sensor on the rear roll bar Ahh, the ol' SLS/LADLPV then... doh! How silly of us! bwahahahaha!