aux cooling fan

[cavx5]

hi everyone...can someone explain to me how the electric aux cooling fan works in the x....is it on all the time or does it cycle with the engine temp...also when i shut the the car off will the fan turn on to cool the engine qm.....my other cars have a fan that turns with the drive belt and then the electric fan as a supplement...the x has only the electric fan....thanks rob

[Werewolf]

Originally Posted by cavx5

hi everyone...can someone explain to me how the electric aux cooling fan works in the x....is it on all the time or does it cycle with the engine temp...also when i shut the the car off will the fan turn on to cool the engine qm.....my other cars have a fan that turns with the drive belt and then the electric fan as a supplement...the x has only the electric fan....thanks rob

The Aux cooling fan is actually a weakpoint in the x5 design. The transistor goes and fan shorts creating a slow eletrical drain on the battery.

I believe the aux cooling fan activates when the car senses the engine temp is above a certain number and the vehicle is not running (engine off). It should not be on all the time.

[cavx5]

i dont know today i was experimenting a/c was on and i drove about 15 minutes and when i stopped kept engine running opened hood and fan was on...when i shut off car fan stopped turning and did not come back on...i thought fan should turn on and off when engine gets to a certain temp...then if it is a hot day even after you shut off the car the fan should turn on until engige is cool and then shut off...i dont think mine does that...any opinions thanks rob

[Weasel]

The DME controls it depending on a number of variables, won't act the same all the time.

[Zulu95]

With Ac on fan on all the time. With AC off fan on and off as required by sensor. After switch off it can run on for a few minutes to cool engine then switches off until you start driving again. If it cycled with the engine off it would soon kill the battery.

[bgsquad]

As weasel said, it depends on many parameters. I have it on only after driving uphills in a sporty way for 20 minutes... it's always the same running engine temperature on the gauge, but for some reason, after putting stress on the engine, the aux remains on after i turn off the X.

[rubin]

When you´ll start air conditioner then the aux fan still run "normal" to keep the cooling fluid colder. The DME can with this fan controling the motor temp an the temp of cooling luguid, too.

[urcbmw8]

I have 2001 X5, and I am having the same question regard to the aux fan that is sitting in front of radiator, does this fan for A/C or radiator? I notice the main fan inside engine area works fine every time I turn on engine except the aux fan outside. It looks like it does not cycle even though I turn on AC but my AC works fine, it is cool as normal. My temp is still at the middle even I turn on AC all day but I smell kind of burning coolent. By the way, I just had my radiator replaced because it broke. Does anyone have any idea about the aux fan, does it suppose to cycle all the time or cycle whenever it is hot. Please advise.

[Weasel]

The aux fan is controlled by the engine computer, and is only turned on when needed. It can operate for just coolant cooling and/or for ac, but only when the DME see's it needed. If your aux fan never comes on it is probably bad, but it is hard to confirm without BMW GT1 diagnosis. If after a long drive when the vehicle is at full operating temperature with the ac on max it doesn't come on after sitting at idle a minute or two I'd think it may be bad...

[TerminatorX5]

Any one knows if the Aux Fan in X5 runs off resistors or runs off the some kind pulses from the control unit? I have read in various places that there are two kinds of operating options for this fan... maybe more... That fan is not kicking on when the temp is reading 119degrees Celcius in my car. 119 is waaay too much for the cooling system... and that fan by all the means should kick in and it does not...

Where is the fuse for that thing? Glove compartment? is it that 50 A (!) fuse? that is a lot of amps!