Hi,
I previously made a post on the deisel forum but I will put it here just in case. My C220d engine started to knock during a long drive back from work. The knock gets louder in lower gears. The car has done 125,000km and been serviced at regular intervals by a local garage since my ownership for 2 years (3rd owner). Engine power seems fine and the car is driving, but it does not sound safe to drive. Oil level also looks good, I got it serviced just last month. Im booked in with a local mercedes specialist this week. Any ideas on what it could be and what could have caused it? I’ve researched a bit but cannot find something conclusive with the OM651 engine atleast. I will link a video of the sound below. Any help will be appreciated.