^ Bumping an old thread I came across...

we never positively identified this... nor the threads about the fan noise coming from the right-rear wheel well either.

plausible but how come the e53 never made this noise?

hi guys i hear this sound all the time but it only makes it when the engine has been running for a period of time and if you stop the car, if you quickly get out you hear some motorised actuators either opening or closing then a whoosh sound of air escaping, .. many of my friends have commented on how cool it sounds. ill record it on my phone and upload it when i get time, it does apear to come from the driver side wheen arch is this where the air filter box is housed??