The dual-mass flywheel is one of the most frequent expensive repairs on the OM646, especially on a manual car driven in town. Rivets hold the two discs together, and they can shear, which makes the flywheel run out of balance. It typically goes between 150,000 and 200,000 km, depending on driving style: a lot of setting off in town wears it sooner. The symptoms are vibration at idle and a metallic rattle when using the clutch. The imbalance can also ruin the clutch disc and the crankshaft sensor, so one flywheel fault turns into the replacement of several parts. The job is also expensive because the gearbox has to come out for it.