Hi
I have w204 with m272 engine and 119k mi
Recently I am having knocking only when warm startup and its start after 2 seconds of the engine start and keeps going for 2 seconds only
But the funny part is there's no sounds what so ever in cold startup !
Here's 2 videos on YouTube who have similar problems
Thanks
https://youtu.be/D-95-cyv7B4
https://youtu.be/n0uwx2Nn2W4

I’ve had the same noise in the same conditions since new. 2008 C300. 250k mi and16 years later, it’s still there. Call it character and don’t you dare crack open an otherwise healthy 272. There’s nothing to gain.

Thanks for the reply
​​​​​​What about diagnosis from mechanics or anything? Aren't you curious to know whats the problem?
For me i added lucas synthetic stabilizer and changed oil filter but no luck ...
​​​​​​

Any luck ?

Nothing yet

Cars can make crazy noises as they go over 100K so if it causing no problems its prolly not worth looking at. Also since it only does it at certain times it will prolly be difficult to find and fix.