My engine is making a weird whirring noise, can anyone identify what is causing it?

I have uploaded a video to YouTube of my 2004 Fiat Punto engine. The previous owner did not take great care of it and when I got it I had to put almost 3L of oil into the car so I think there is damage to the engine after that, however it has been running OK. Is this sound a big problem or is it just the old engine sound?https://youtu.be/1rbsN5w9Wqs via /r/cars http://ift.tt/2tMfgYD