Hi Beach Benz, yes the timing chain set-up on the M103 engine is usually trouble free. Before you start tearing stuff apart I think you should take a close look at the belt tensioner/damper. When the damper fails it can cause a very noticable rattling noise. Look closely at the damper mount where it attaches to the bracket on the left side of the upper front cover. Sometimes the bushing is visibly worn. If it looks OK try this. While you can hear the rattle, push on the damper with a suitable tool ( wooden hammer handle, large screwdriver). If the damper is causing the rattle, the noise will decrease when you put pressure on it. You'll also feel a heck of a vibration. Good luck.