Electric Fan

[rocketir]

I have the 3.0 X5. Popped the hood and I noticed that I have an electric pusher fan as well as a mechanical belt driven fan. Is there any reason for having two fans? When does the electric come on? I haven't noticed yet as I have only had the x5 for a couple of weeks and I don't drive it everyday.
On my other vehicle I had a mechanical but replaced it with an electric fan.
Jesse

[batman]

The electric fan comes on as necessary and even after engine shutdown for up to 10 minutes.

[withidl]

The electric fan also comes on whenever the air conditioner is on.

[rocketir]

Why do we have the mechanical hanging off the motor then? I would like to go strictly electric if I could. Also what use is it being on when the motor is turned off, the water pump is off anyways.
Jes

[JV]

Originally Posted by rocketir

Why do we have the mechanical hanging off the motor then? I would like to go strictly electric if I could. Also what use is it being on when the motor is turned off, the water pump is off anyways.
Jes

I am not sure about this, but possibly the water pump is partially electric? Would make sense that BMW engineers would think of this- belt-driven water pumps are horsepower parasites- but I will have to investigate further to be sure.

I've used electric aftermarket water pumps before, they typically flow only abut half the volume of a belt-driven pump, and they're huge compared to your standard pump, I'm just hypothesizing now, I'll have to look under the hood.

EDIT: Just thought of this, maybe the two fans arranged in the series like they are (in front of the radiator and behind) are in a push-pull setup? This would increase airflow greatly. I suppose the electric would continue to pull air into the engine compartment after engine shutoff to cool the headers, etc.

JV

[ATCX5]

Dropped some non-perishables in a box at work today that's promoting some food drive along with your station...thought you might like to know, possibly a plug for NATCA???
Thanks

[JV]

Originally Posted by ATCX5

Dropped some non-perishables in a box at work today that's promoting some food drive along with your station...thought you might like to know, possibly a plug for NATCA???
Thanks

You're the man, thanks for that. Hey, the FAA is gonna need controllers like crazy soon, lots of you guys approaching the big golden govt. parachute! I could certainly recommend air traffic control as a career choice to the area youth! Seriously, I'll throw ya an on-air bone for that kind gesture, man.

Sorry that ATCX5 and I hijacked, now back to your regularly scheduled thread.

JV

[tsagg]

Anyone have a VERY loud electric/aux. fan in their X? Mine hums like a bastard and can be heard over a fairly loud radio.....comes from corner of the engine bay closest to the driver and ONLY when the A/C is on. Of course the dealer says its normal. I've had other BMW's and have never had this loud hum before.