Looking at various comments on this issue, I would like to add a few words…
Since Valvetronic engine and engine oil interval done at 25,000km, all engine oil viscosity now has been revised to 5W30 or 0W30 (or equivalent – meaning thinner viscosity) due to tighter engine tolerance. Using thicker viscosity meaning no good to engine since the engine oil cannot go to tight freeplay areas properly. If no oil there, mean friction. Friction means reduced engine life..
By its natural character, thinner engine oil means the oil now more tangible to vaporizing rate. If you open up the oil filler cap with engine hot, you can see the oil vapor clouding the valve train area.
And by considering the BMW engine construction, the oil vapor will be collected by an oil trap beneath the intake manifold. Liquidized oil will returned to the oil pan. Excess vapor will be channeled back to the intake manifold where it will be drawn into the combustion chamber (burnt!) and later thru the catalytic converter so that it won’t pollute our breathable air.
This is how the engine oil loss comes.
According to BMW specification, maximum permissible engine oil consumption is approx 1 liter for every 1,600km…
So, in this case it is normal for you to have the engine oil added after the car has covered few thousand kilometers since last oil change.
I think no other car makes that has engine oil interval done on every 25,000km… dun worry if you need to top-up between the oil service as far its does not takes you beyond maximum permissible range.
I will check the list of approved engine oils for your BMW later…