With the M112, this happens due to the lack of frequent oil changes as per recommendation by Mercedes. Yes, it is technically well within specs as I believe the limit is something like 1 quart per 700 miles or so. The truth is that the engine is starting to show signs of problems and hopefully it does not get any worse.

I believe the most common cause of consumption is the rings. Since the engine uses low tension rings, if significant amounts of sludge build up as a result of changing the oil every 12k miles, then they can stick to the piston and allow a lot of oil to flow through to the consumption chamber.

Again, 1 quart per 2500 miles is not that bad, but monitor it and hope it does not get any worse. You won't get anything out of the dealer other than "it is normal" until you get well under 1 quart per 1,000 miles.

__________________
Ali Al-Chalabi

2001 CLK55
1999 Dodge Ram 2500 Cummins Diesel
2002 Harley-Davidson Fatboy
Merlin Extralight w/ Campy Record