Have an e60 528xi got the low coolant level alert so I filled it and for some reason it only took about 1/4th of a gallon and it was on max. One week later same notification. The e60 holds 2 gallons correct? If so then why is it max after only adding a 4th of a gallon since I got the low coolant notification. Thanks in advance

 

The coolant reservoir tank has a sensor in it that knows when it is low. That is the little stick thing that bobs up when you remove the cap. If only a little leaked out, then not much is needed to correct the level.

Your problem is to find out where it has gone. Having to top-off twice in the space of a week means you got a problem someplace.

 

Coolant Reservoir Tanks are known to crack and leak. Check to see where the coolant is leaking. Your coolant loss is pretty significant. There should be evidence of the leak. Check all hoses as well as the coolant temp sensor on the lower hose by the radiator. There is also a coolant return pipe that runs along the top of the radiator under the cover for the hood latch. The plastic becomes brittle and can crack. I have replaced all 3 for a similar leak. Good luck and be safe! Remember this coolant is hot so use caution!

 

Thanks for the direction Hyper. I believe I narrowed down my slow leak to the radiator hose on the top of the radiator. Amazon will be shipping a new one tomorrow