Hi Everyone,
I'm new here having just bought a 2010 E70 X5 35d XDrive.
One of the urgent problems facing me is a low coolant level. When I bought it the level was below the Min mark. I asked the owner and he swears he has never had to top it up. As he is a friend, I believe him and I have to assume the problem is new...

Anyway, I topped up the water to the Max mark and after a 25 mile drive it was down to half way between the Max and Min. After not driving the car for 3 days, the level is now down to the Min mark.

So should be easy to find if it is coming out on its own, but I can't see any obvious signs. There are some white marks below the crank pulley, seen from underneath, but that's all I see.

Can anyone make any suggestions of where to look? Btw oil on the dipstick looks black...