C220d 2019 rattling sound under the hood (video included)
It has been going for over a month now, it just randomly started mid-drive over a month ago, and back then the sound was actually very quiet and inconsistent. But week by week that sound came more loud and frequent, and now it happens all the time as you can hear from the video.
The car went to MB's troubleshoot, but they couldnt locate the issue. They said the rattling sound changed to kind-of clunking sound when the AC was turned off, but I dont hear any difference whatsoever.
Before the sound came frequent, I noticed it happening the most always after I released the gas pedal. Never during acceleration, braking, nor going over bumpers.
Here's the video to judge:


