Can't figure out what's causing this noise in engine

The noise is a little hard to describe so I've attached a video for anyone able to help me and give a listen. Anybody have any idea what could be the cause of that horrible noise? It's a 2012 VW GTI TSI 2.0L engine with turbo. I don't hear any noise from inside the car and it's not consistent either. Any ideas of where to even start investigating would really help! Thanks



https://www.youtube.com/watch?v=36o4VUUJSV8

Gonna go out on a limb and say water pump

I thought that at first but it doesn't sound like a whistling noise, plus water pump and drive belt were replaced a year ago but maybe it's still not fixed...

Unless I'm missing it, it sounds like direct injection.