Driving me crazy!
 

Recently I posted a thread involving a fluctuating humming noise that you can hear while idleing.It stops when you turn off the circulating fan.I have talked to my tech and he said that is normal and other X5,s do the same thing.Do any of you have this same humming noise and is this normal.When your driving the engine is noisy enough to cover up this noise but at a light or stop its pretty noisy.

This was covered already, yes it is normal to hear a 'fan' noise when the system is on.

http://www.xoutpost.com/x5-e53-forum/...en-idling.html