[bimmer456]

So I notice after some spirited driving on a hot day the car will run the radiator fan for about 5 minutes after turning off the engine. Since BMW switched back to a mechanical water pump after the reliability problems of the electric water pump failures with the e90, it would seem not to serve a purpose since the water pump doesn't operate with the engine not running. What do you think?

[anotheran]

Originally Posted by bimmer456

So I notice after some spirited driving on a hot day the car will run the radiator fan for about 5 minutes after turning off the engine. Since BMW switched back to a mechanical water pump after the reliability problems of the electric water pump failures with the e90, it would seem not to serve a purpose since the water pump doesn't operate with the engine not running. What do you think?

it's to cool the turbo. Similar to this thread: http://f80.bimmerpost.com/forums/sho....php?t=1089216

[bimmer456]

Originally Posted by anotheran

it's to cool the turbo. Similar to this thread: http://f80.bimmerpost.com/forums/sho....php?t=1089216

makes sense. I assume the turbo cooling pump also works prior to starting, that's the secondary motor sound coming from under the hood after the water pipe wooshing sound coming from the rear of the car when you unlock the door, being the low pressure pump priming the fuel system so as to put less strain on the high pressure fuel pump that is prone to failure in the E90. Now ironically the low pressure fuel pump is being recalled on some earlier F30's.

[skw]

Originally Posted by bimmer456

makes sense. I assume the turbo cooling pump also works prior to starting, that's the secondary motor sound coming from under the hood after the water pipe wooshing sound coming from the rear of the car when you unlock the door, being the low pressure pump priming the fuel system so as to put less strain on the high pressure fuel pump that is prone to failure in the E90. Now ironically the low pressure fuel pump is being recalled on some earlier F30's.

I had the lpfp go on my '14 F30.