96C280,

You did a great job explaining this situation. I just went through exactly the same symptoms this weekend and was thinking of how to ask the question. I have looked under the hood and nothing I can see could have caused the thumping sound.

The temp in my car (1993 300E) did not go quite as high as 120 degrees despite a 45 minute crawl through Santa Barbara, CA. But the sound came during the traffic crawl and again today during a short drive from work. This time the temp. was normal (under 90)

I hope we get a response from the MB masters.

__________________
TOOFAST45

'93 300E 2.8 - 138K miles