A/C pusher fan

[R515]

I’ve owned my E53 3.0D sport for about 8 months now and have picked up a ton of info from this forum and thought it was time to put something back in.

Since owning it I’ve gradually gone through and sorted all the faults but the last one was for the A/C pusher fan, it stopped working in the summer, albeit with no adverse effect on either the A/C or engine cooling, just the annoying fault code that I couldn’t clear.

Given that the fan unit is over £500 at the dealer and the best online seems to be MisterAuto who lists one for £230, I opted for second hand with a 45 day warranty from ebay.

This arrived, was fitted and worked as expected but left me wondering if any repair was possible on the old unit given it is electronic as opposed to an ordinary cooling fan.

Dismantling it was straight forward, 3 x 7mm nuts have to be removed before the two halves can be gently pryed apart, this showed the fan blade unit attached to motor windings and the cable section attached to a PCB that was covered in a generous covering of silicone. This section was obviously not for repair but protruding from it were flat pins that push into the motor windings and these were very corroded, as were their sockets in the windings. I cleaned up the pins and sockets with Aluminium Oxide paper until all were bright and shiny again and then re-assembled and tested back in the car. (Just holding the fan by hand after plugging it in to the loom)
To my amazement it worked!  so to all the DIY’ers out there, before you condem a dead A/C pusher fan, strip the old one apart, clean the contacts and see what happens, obviously if you have a PCB fault, this won’t help but it’s worth having a look first.
Regards,
Mark

[X5-D-Sport]

WOW - well done you for fixing it,

what do you want for the motor unit you got working ?

Mine is dead as a nail & looking for a replacement...

[R515]

Afraid I'll be keeping it in case the second hand one gives up and can't be repaired!

Mark 

[Ryoken]

similar, I bought a brand new unit from America  cost me a couple hundred, fitted it , in the well. start dry , in the end raining , lets just say I was bloody annoyed when I fired it up and it didn't spin
so ive either bought a dud or my original fan is ok , and ive another problem.

[X5-D-Sport]

Hi Ryoken,
I had an identical issue, replaced my pusher fan - spent a packet - doesn't work...

Fortunately, I simply removed the 3 bolts from the rad side of the fan motor to remove it - without removing half the vehicle - which was a  huge relief...

Just need to find a way to get the bloody thing to spin..

Any one got any ideas ?

[Ryoken]

well, upon reading a load of info on the interweb and talking to my mechanics at work (royal mail) and my local bmw  indie I have come up with the following

don't worry about it
I spent ages of time looking , getting stressed ( at the time I had a ongoing over heating problem, thought it was the the fan or the thermostat or a bhg, so I had to get the bottom of it .
any whoo, what I can make out is the fan does an initial spin on start up and is only operational with the AC on , its basic function is to cool the AC in standing traffic or extreme temperatures, to basically stop the ac going boom.
when you stop at traffic lights there isn't enough air being drawn over the rad and the ac rad, the pusher fan just helps a little more air over them , if the temp isn't high enough it wont fire up, there are 2 sensors on the hoses thst tell the ecu this figure, ( yeah I replaced them too) still nothing
  and in the uk you wont ever need it . I posted in the xoutpost about this and people in the usa even though there fans are working ok , never need it , its just an extra bit of cooling if you decide to go to somewhere that requires extra cooling

this is only info ive been told , or worked out ,


so if it doesn't work , id test the fuse, or make sure you have the ac filled, mine was empty so it didn't work anyway, if your asc works ok (get it recharged) forget about it

[X5Sport]

You still need the fan regardless.  The US system isn't identical to the UK version either as their temperature ranges are different to ours (more extreme at both ends).  As the engine warms up you need the pusher fan to keep sufficient cool air running over the condenser radiator at low speed or when stationary.  If there isn't enough flow then you get much less cooling.  Low gas pressure will completely stop the system itself from running as that is part of the compressor protection system, but you still need the fan working to give full climate control all year round.

The fan speed varies with the environment temperature - hence using a pulsed control signal rather than a simple DC supply - and hence it sounding like an aircraft in summer but quieter in winter.