Got the coolant low warning a day or two after driving a hard hour at the track... Is this expected behavior? The engine was serviced at 20k miles and is at 44k miles now. I used to have to fill my Volvo up with coolant because of a warped head, ugh. My BMW is a 2007 550i.

 

Its normal to top off the coolant every once in a while.
Regards.

 

Did you change the battery? Same thing happened to me and dealer said it was a battery fault!! Tech stated the coolant was a little low tho!!!!

 

Thanks 968TurboS.

kane1111, no, no recent battery change.

 

Word of caution. I have a '06 530xi and had t2o low coolant level warnings in the space of 1.5 months. I had the local dealer take a look and lo and behold it shattered a hose when it was pressurized.

The coolant system is a closed system and therefore should NOT lose as a matter of normal operation.

 

I would say that you have a very small leak. When you push car harder on track the pressure in the system is higher causing bigger coolant loss.

Take the flashlight and look for blue\white coolant stain on the engine or bottom engine shield.
V8 has few common places of coolant leaks:

1. Temp sensor on the lower radiator hose (13621433077)
2. vent hoses (17127542540 and 17127534917)
3. Valley pan (11147507278)

http://realoem.com/bmw/showparts.do?...51&hg=11&fg=10

4. Water pump
5. Small crack in the expansion tank (17137542986)

See the diagram
http://realoem.com/bmw/showparts.do?...86&hg=17&fg=05

 

You probably have a small leak in a hose. I used to have to top mine up every 5k miles and then they detected a leaking lower radiator hose and temp sensor. $275.