Ken, the part numbers in the EPC don't match the casting numbers (same as with the cylinder heads). When you get time check the new cover, please let us know what the casting number is, stamped on the front; and also what the differences are (when you eventually start working on it). Oh, I have the Haynes manual too, I'll look at that.

Carrameow, that makes sense - head stays in place but oil pan drops down. Hmmm. I know it can be done with the engine in the car but with the very limited room to work on it, I'm thinking it may be easier to just pull the engine and be able to fix it on an engine stand. And you can't sell the car now that it's all fixed up!

BB, nope, the alternator didn't cause this. It's almost new and spins freely and never makes any noise. Any locked accessory (alternator or otherwise) should never cause this kind of failure - period. Mercedes redesigned the timing cover twice, I really suspect there is a change in the area of the tensioner threaded hole...