I've got a 99 ML430, sometimes the starter will not disengage when I try to start it.(randomly) It does it after it has been driven. I pulled the starter and took it to a shop to have it rebuild. The mechanic took it apart and said it was good and strong. He went ahead and replaced the solenoid. I still have this problem. I talked to another mechanic and he said this is a common problem with the ML's and you have to put some Anti-seize on the flex plate. I did this and it seemed to help but it still randomly does it. I'm feeling the heat from the wife.

Help!
Keith Davis

Never heard of this problem. Are you sure its not a failing Crank Position Sensor? If you have the original CPS, that might be the problem. Cranks but won't start when the engine is hot. My 2 cents.

Not to sure. It's fires ,start and but does not disengaging and it kills the motor.

Where is the "flex plate"?
My ML sounds like the starter motor has a hard time releasing (a screech noise) in 10F winter weather. Anti-freeze sounds like the cure for it (even if the dealer has no clue :-)

The Flex Plate(sometimes call the flywheel) is between the motor and transmission. You'll need to use Anti-seize not anti-freeze. There's (2) small plastic plugs at the front of the transmission. You pull those plugs and you can see the gears on the flex plate. The anti seize I used had a brush, so I put some on brush stuck it in the hole and had someome bump the starter.

Mercedes has a special grease for the ring gear.
http://www.peachparts.com/shopforum/tech-help/181829-1998-c280-starter-runs-too-short-post1445929.html