In Reply to: Many opinions but nobody here knows real answer. posted by noka on March 09, 2002 at 16:46:08:
The race bred engines incorporated in BMW M vehicles include increased power output and
maximum engine speeds compared to conventional BMW engines.
Due to their high performance design characteristics all M engines may exhibit slightly higher oil
consumption compared to conventional BMW engines.
A spirited driving style (especially during the critical engine break in period) will lead to further
increased engine oil consumption.
BMW recommends checking the oil level and if necessary topping up using the correct viscosity
whenever refueling is required to maintain the value of your BMW throughout its service life.
Furthermore, M5's produced up to 3/00 require 10w60 as opposed to M5's produced after this date, which BMW recommends synthetic 5w30. I know this does not necessarily answer the question of *why* M5's consume so much oil, however it should be comforting to know that it's not just an unacknowledged quirk with the car.
Did anyone read the Roundel from a month or two back in which the BMW master tech wrote in regarding this issue? His answer was essentially that it's extremely hard to make a racing engine that does not consume oil, and that M5 owners should realize this.