[Bikerjoy]

Originally Posted by seriousm3

numerous oil analysis on M cars have shown that oil starts to break down after about 8000 miles.

I'd be interested to se data and not a mere statement on that! Although I think you are technically right, for argument sake you could probably claim that oil starts to break down from mile 1 not 8000, the real question is if it has a true effect on the engine or not.

Originally Posted by seriousm3

BMW engineers didn't come up with the free maintenance idea... that was the marketing department.

Technically you are probably right here also, however, isn't that a little short sighted? I am sure that the push for 18k maintenance interval was "market driven", but I would sincerely hope that it is also backed up by some engineering making sure that the product won't break down because of a decision made by marketing guys. Word would get around pretty quick if M cars were to all break down right out of warranty.

There really is no great conspiracy here. I am simply stating the fact that the US is VERY different from most of (if not all of) Europe replacing oil every 5k miles. The fact that americans still insist on doing it is probably partly tradition and partly market driven too. There is big money to be made in replacing oil every 5k miles. How many commercials do you see every day about engine sludge? If anything I would say that the 5k oil change is a product of a marketing guy and not an engineer!