Patsy, If you have the MB service manuals, check the one for "Engines 615,616,617.91"page 05.4-215/5. there it tells about replacing timing chains.If you do replace the chain, how about the cam sprocket gear? It probably gets more wear than the chain. Make sure the tensioner is good. It's there to keep the chain good and tight. When I do replace a chain, I will always replace the cam sprocket and the tensioner if needed. Good Luck
Bill Lewallen Lexington,Ky.
If I listed all the Mercedes I have owned, It would take up to much space. Let's just say I have owned a few.