Benzadmiral,

Maybe it's worth a call to an MB dealer in your area to see what oil they use. I'm in Canada and the local dealer has been putting 15W40 dino oil into my 95 E320... probably same oil (viscosity wise anyway) they'll put into a 97 C230.

I've also looked up my owner's manual and like you said, it does not show any chart but refers people to the dealer. Maybe that gives some leeway for dealers to adjust for local temperature range?