Later cars run warmer than older cars seemingly by design. It freaked the heck out of me when the S420 topped 100*C in traffic. My sensitivity stems from having the SDL which as yet hasn't topped 100*C with the new head. I was told that 100*C and even 110*C are not extraordinary events for the S420. My validation is that it stays below 90*C when it's moving.

Check JimF's website (http://pages.prodigy.net/jforgione/MB_S500.html) for more info and possible tweaks to keep engine temp in check... if it applies to your car.

Sixto
95 S420
87 300SDL