After a short suburban ride where brakes were applied on many street corners, I park the car and turn everything off. Then a type of fan sound comes on but only in the right rear wheel well. I assume this has something to do with the 'brake fade compensation' feature of the X? This is the first time I've heard a fan go on after the car goes off. It lasted a good 3-5 mins. I have started using sport mode too so maybe something for the suspension?

__________________
'08 X5 3.0si - Alpine White / Saddle Brown interior
Specs: Sport Pkg, Premium Pkg, Tech Pkg, Comfort Access, Aero Kit, Style 433 staggered 20s on Conti DWS
Mods: Carbon 35 tint, LED angel eyes, GP Thunder 7500k fogs, H&R 20mm/25mm spacers, clear reflectors, gunsmoke-tinted taillights
Coded: Digital speedo, windows/sunroof/tailgate close via keyfob

X5 pics at Flickr