Knocking on cold start w205
Thread Starter
Newbie
Joined: Jul 2024
Posts: 5
Likes: 0
W205 220d 4matic
Knocking on cold start w205
Hey guys, my 2019 c220d with om654 engine makes this terrible knocking sound when starting it with a cold engine. It won’t happen everytime but often yes (always only when starting the engine for the first time of the day). Also it sounds to me like a chain rattle noise in the background but cannot be heard very well because the knocking noise is too loud compared to that. What do you think it is, or maybe anyone experienced something similar and what’s the fix? Is it the timing chain or its components like the tensioner or it could be something else?
Last edited by Meco000; Jan 5, 2026 at 10:45 PM.
