hi, about a month ago I have bought my first diesel car, a 2003 1.4hdi 307. So I can say I'm quite new to a lot of things. A week ago I have noticed this noise coming out of the engine ( https://soundcloud.app.goo.gl/eqs48 ), sometimes it is there no matter how long the engine has been on, other times it is not there at all. It might be something with the belt, maybe a bad tensioner, or a bad tensioner spring? I cannot spot a problem while driving it, nothing has changed, it is just a bit alarming to my ears. Does anyone have any ideas? And should I prepare my "life's savings" and rush to get it fixed?