First, thanks for the replies. I really appreciate your time.

At this point in time, my engine runs like a charm. No clacks or rattles.

Sorry to be dense, but can my model and year have different engines? If so, how do I know which one I have?

I have heard that some of the MB engines do break their timing chains so it is very confusing. AND -The dealer keeps saying (last three visits) that they need to change it before it breaks.

I really didn't want to get the timing chain done if it was not absolutely necessary. But I know I don't want to wait for it to break.

They said they need to take the valve covers of to check it and that is why it would cost me $200 just to check.

Last, I am not sure if I am posting this back to the thread I started or somewhere else. Hopefully I will see it in the right place!