check out the above website and do a search, I have owned several diesel trucks, fords and chevys. They all blacken the oil quickly after an oil change. this is called sooting the oil. the better oils have whats called "soot control" which suspends it. a very good dino oil if thats what bmw requires in chevron delo. as far as synthetic i never ran it beacause it was too expensive. my belief with a diesel is to run a good dino oil and change it often. good luck. again all my trucks were new which allowed me to break them in... they still blacken the oil quickly.

chucker

__________________
09 X5 4.8is, Saphire black w/ black guts

10 528i, Alpine white w/ black guts

89 m3, Zinnabar red w/ black guts