2011 Mercedes-Benz C200 has timing-chain stretch

That’s not a huge mileage for an engine like this, and I wouldn’t expect to see timing chain stretch over that distance. However, it begs the question of how the vehicle has been serviced. Timing chains really should last the life of the car (or, at least, the engine) but if the engine hasn’t been treated to the correct oil changes and general maintenance, the timing chain can be one component that will suffer.

If the car was bought second-hand, it would be worth going through the service history to see if any scheduled servicing was skipped. This could be the root cause of the problem. It’s also important not to confuse a stretch timing chain with a worn chain tensioning system. The tensioner holds the chain tight, taking the slack out of it and allowing for some stretch to be taken up over the years of operation. If it fails or becomes weak, you might start to hear the chain rattling.