There has been lots of discussion about this subject. My ML has minor leaks after switching to synthetic. It bugs me more that it's dripping on my garage floor than anything else. Some people have been told by MBZ that it's normal to for the ML to use a quart every 1000 miles! Imagine that! I don't think it's normal for ANY car to use a quart of oil every 1000 miles. For some cars with a 5qt capacity that's an oil change every 5000 miles. Check out this thread...

http://www.peachparts.com/shopforum/showthread.php?threadid=18745

Kuan