Noise from the engine

Hello, my car is a 2.0hdi 406 and sometimes I hear a noise like the one in the video from under the hood. When it makes this sound, I also have a misfire problem in the car. I took it to the mechanic 2-3 times and it doesn't work anymore. The guy says there is no sound and sends me back. Has anyone experienced this or have any ideas? I would appreciate it if you could help me.[TUBE]https://youtube.com/shorts/2jjpH32t4Io?si=Wf0ZqfX01Gtf7SeC[/TUBE]