best1

At 65,000 my electric fan was only working intermittently. I did not have a coolant leak though.

ETNav382

During the winter up here in Washington state I had the same message, the temp those days was around 20F. I filled it up with distilled water once or twice and even thought I had a leak. I finally called the dealer and they said its normal for that warning to show up in the winter and if I brought it in they'd top it off for free. After they did that I haven't had the message since. Funny thing is the warning would go away once the car warmed up, I don't know if that means anything but I haven't had a problem since the dealer so it might not be anything at all.

turboawd

if you cant find the leak, as a last resort, you can try a stop leak product and add it to your coolant. i'd research which are or if they are recommended by bmw.

you may also try a uv dye that you add to your coolant to see where it leaks.

sotek

Stop leak is bad stuff! But a last resort as you mentioned. I'm now having this problem.. low coolant level warning. The top of the float thing is at the mouth of the reservoir when I open it - I assume that means full (maybe I'm wrong!!??). It seems to come and go.. If i leave, make a stop and restart the car, it goes away but comes back the following day. It's happened a few times but there is no visible loss of coolant. I did notice a little white stuff in the coolant reservoir floating but not a lot, maybe a teaspoon. This was when it was cool. I'm "car stupid" so didn't want to go messing with a hot engine. (common sense prevails LOL).