RamblingMan

I hear a fan or pump after I shut it off, even if the engine had not been running. Anyone know what this is? I'm sure it's normal. I'm just curious what it is.

dudley@07726

RamblingMan

I have a Premium Plus like you. The 3.0 in it is supercharged. The 2.0 engine is turbocharged.

ByByBMW

Just noticed this recently after the diesel fix on my A6. It's the radiator fans running and I assume it's to cool down the turbo. But it never did this before the TDi fix.

porksoda

Few clicks as well after you turn the engine off from the engine bay.

John Simcox

On the TDi more likley, you have switched the car of mid-regeneration of the Diesel Particulate Filter. If this happen the cooling fan continues to run to help dispate thehigher temeratures associated with the regeneration process. You'll probably notice an unpleasent burning smell towards the rear of the car as well

dudley@07726

ByByBMW

I initially suspected that but have no unpleasant smells so??? But I also suspect you are right since this has happened twice in the last week. Used to occur once a month or so before the fix.

Fahrer

What year and engine do you have? Some of he newer engines have the exhaust manifold built into the head. This provides quicker warm up of the passenger compartment ( the head and block have different circuits). It also reduces the need to enrich the combustion mixture when increasing load resulting in better gas mileage. However, the coolant in the head can boil after shutdown so an electric water pump circulates the coolant to prevent this. Of course the electric fan can/will run as well.

tenspeed

I don't know what it is but my 2012 A7 3.0L gas engine does it too. Sounds like a relay closing and some whirring. It doesn't last long and the engine still starts so I'm good with it.