Here's a new one that just started. I just replaced the water pump on my 92 300E (103 engine) and, now, there is a tapping noise coming from the front area of the engine. It seems to be in the area from the timing chain cover over to the right (as you are facing the vehicle)to the water pump pulley. The sound goes away after the engine has warmed up. I do know that this type of sound on a 420SEL or 560SEL indicates timing chain issues, but, could this be the same thing here? By the way, 169,000 miles on the car. Or, could it have something to do with the water pump replacement? Any thoughts? Thanks in advance.