Hey All,
I was gonna ask around for opinions for the engine noise I was experiencing, so I made a video about it. But, before I uploaded it I found out what was going on. I`m sharing it anyway, just for the ones who run into the same problem:
https://youtu.be/9e6TqgnNqUs
To me it sounded like a "metal grinding intermittently on metal" noise, but I was totally wrong. I removed the belt but it didn`t go away. It comes on only when the engine is warm, stops when I hit the accelerator and its frequency is ~400/min, exactly half of the rpm at idle, which is a great hint
It was (highlight the following text by clicking and holding down the left mouse button if you don`t want to guess):
loose spark plug