By far, the most common cause of excessive oil consumption is worn, or sticking oil rings. The cure is to replace them. This requires a complete tear-down of the engine, and close inspection of the cylinder walls. If excessive scoring/wear of the cylinder walls is found, we replace the block, along with a set of factory-fitted pistons and rings.


The few occasions I've seen MB refuse to help were when the criteria outlined in my original post were not met. If the documentation doesn't support the claim of excessive oil consumption, or, if the vehicle hasn't been serviced properly, MB won't do a thing about it. However, if the paperwork is in order, there's never a problem. So far this year, my shop has done about two dozen re-ring jobs, and three engine block/piston jobs, on vehicles that were well out of warranty. In each case, there was no problem getting MB to pay for the work.