power steering pump cooling fan stays on... Why?

[1rabbit]

Hi

Hoping someone can shed some light on this big problem. I have searched for a while, but without any good results. (MCS 05)

Last night I drove about 50 mile trip home, parked, turned the engine off as normal, went to bed. Went to open the car this morning and everything was dead. Had to open the door with the key instead of pushing the button on the key to unlock. Everything in the car was dead. No light, no nothing.
So I jumped started the engine and everything sprung to life. So my battery was dead.

Took it for a spin, and turned the engine off again. I can hear a low pitch sound coming from the area around the Coolant expansion tank. Its difficult to precisily locate it. Anyway, after a while I tried to start again, and the battery was drained yet again.

It is as if this noise is draining my battery some how, but I have no idea what it is. Everything looks turned off, but something is still on after I turn the engine off.
Has anyone experienced this problem before, and has anyone a clue what it is. It looks like the battery will be dead again soon if I dont restart shortly... Thank you in advance.

[helicopter pat]

It May very well be the power steering pump cooling fan which is mounted on the pump behind and below the engine. It happened to me about 18 months ago.
Pat

[1rabbit]

How did you manage to fix it? The only way I can switch it off is by disconnecting the battery(which I have just done). I suppose on monday, I will have to take it to the dealer... but how did you acheive a 'fix'? Or did you simply take it to the dealer?

[1rabbit]

Ok...been reading heavily into this for the last 2 hours. Thanks for the tip 'power steering pump cooling fan'. It still seems a grey area.
Does anyone know why this cooling fan is still running after the engine is turned off? Could it be a faulty sensor or something? Whenever I connect the battery, this fan turns on and stays on. Well weird if you ask me.

[helicopter pat]

I think it was the temperature switch that was faulty on mine. New steering pump fitted by dealer under warranty.
Pat

[1rabbit]

Just to clear up this thread...

After all that messing about last saturday, I dissconnected the battery in the boot, and connected it up again for monday morning. Took it straight to the dealer, and they immediately replaced the Power Steering Pump and Fan. Apparently the problem was the switch which was stuck in the on position. Apparently BMW are having so many problems with these, that they are replacing the whole unit. Thank you 'helicoper Pat'...you were spot on.

[Keith]

I had exactly the same problem. There is a fuse for the fan that I pulled when I stopped and put back when I started again to allow me to keep using the car for several days until it was fixed. It needed a whole new fan assembly. The strange thing is that it fixed itself after several days and then the problem returned weeks later. I am guessing a relay in the assembly was sticking on.

[Lawrothegreat]

My entire power steering pump now remains on, just after switching the engine but leaving the key in the final position before starting. I didn't realise the power steering could operate without the engine (front wheels actually turn easily), and I'm assuming this isn't normal - so its a trip to the dealers tomorrow.