Noisy Fan problem - BMW 320i ES (170 bhp) automatic ..2007 (57) model
Auxiliary pusher fan comes on after driving 5 miles and its very noisy. I can feel vibration on steering wheel also. I am not sure why that switches on so quickly while its a very normal driving on empty road with 40-50 mph speed, so dont think engine is excessive hot. And the noise is very loud look like a vacuum cleaner noise.
The electric fan should be loud enough to hear, but no annoyingly loud. Maybe the motor is going bad. As far as why it turns on so quickly, it could be a faulty reading from your ECT (engine coolant temperture) sensor, or your thermostat isnt opening up fast enough or all the way so the fan is compensating to keep temps in line.
sugest you try a new thermostat. its a easy do it yourself jjob. also check your sensors?
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