Sorry to hear about the problems with your ML. The statement I got on my TE was that oil consumption up to about 1 quart every 800 miles is considered acceptable. BTW my TE was going through oil at a rate of a quart every 600 miles, with about 70 K miles on the odometer. They fixed the valve guide seals and that reduced the consumption to a quart every 1,500 miles. They refused to do further fixes.

Still, it’s odd that by changing to synthetic you would have a sudden and drastic change in the behavior of the engine.

Perhaps the change freed up some gunk and some of it got stuck somewhere?

Had you previously followed the FSS? If so you may be among the many with early engine failures complements of Mercedes “reduced” maintenance intervals.

Do you drive a lot in the city or do a lot of short trips?

Anyway, defiantly notify the dealer as well as MBUSA. The more noise you make the better the odds of getting the problem fixed.

Regards

__________________
...Tracy

'00 ML320 "Casper"
'92 400E "Stella"