What kind of 5-w30 are you using? I ask as I know that the Mobil 1 is technically too thin according to what I have read. The BMW 5-w30 is on the heaver end of the 5-w30 spectrum so you may not burn as much with that and I think depending on the oil type it may have a higher flash point so it won't burn off as readily.

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2013 X5 xDrive3.5i Premium
2002 530I Sport Package
2001 X5 4.4i
2001 M3