Hi guys, having read a number of posts regarding timing chains, there seems to be some ambiguity as to when,or if indeed ever it is necessary to change the chain.Having had vehicles in the past with cam belts that have snapped and having to deal with bent valves etc makes me slightly nervous. Would be grateful for some idea of crucial mileage marker,or initial signs/symptoms of pending failure. I have also noticed more failures reported on the more powerful engines,is the torque a factor. I have a W201 with 190k on and a W202 with 130k both with original chains. kind regards Martyz.