I remove upper timing cover cleaned it and inspected mating surfaces, you will find small pitting on the timing cover matting surfaces this I suspect is due to age and previous repairs. I actually cleaned up the mating surfaces on the cover by lightly sanding them on a pice of wet sanding paper that I taped on a glass table...the surfaces were uneven and pitted...I used Permanex I also bought the Mercedes gasket maker that was recommended by the dealer it was very similar to the Permanex but it's a thinner consistency.

I found the Permanex was not only thicker but it was more difficult to clean up with solvents, that stuff is think sticky and resilient.

I also replaced the upper to lower gasket with an actually Mercedes Benz gasket, I actually bought the gasket from pelicanparts


http://www.pelicanparts.com/catalog/...ENGCAM_pg2.htm

Gasket - Front Cover to Crankcase
Part #: 104-015-02-20-M30

This is the gasket I replaced