i have a 2008 MCS that every time i shut the car off i hear a buzzing from up front that sounds like it coming from the turbo or vacuum pump area... is this the turbo coolant pump i keep hearing about thats supposed to keep circulating fluid around the turbo after shutdown?

 

Yes. It is the aux pump.

 

I have the same Buzz..weird...So where is this Aux pump located?

 

I would not say that it's weird. If the temperature is above the set point then the aux pump will run.

Item number 2 in the diagram:

http://www.realoem.com/bmw/images/diag_4jto.jpg

 

Mine does that almost every time I turn off the engine, sounds sorta like a fan, for about 30-60 seconds. Maybe it is a fan, but I hear it easily. My 2007 did it too.