Intermittent noise coming from engine bay. HELP!


Registered User
Hi guys! I've been having a weird noise coming from my 2007 A3 1.6 TDI which only happens once in awhile. I took it to a garage but they weren't able to get the car to make the noise and since I don't know why it happens I couldn't replicate it...
I'm even having a hard time describing the noise. I've found a video on youtube of someone with the same issue, hopefully someone on here might have an idea of what it might be?
Here's the video: It's a sort of cycling noise and it happens when the car is stopped in neutral as well.

If someone could shed some light on this I would super grateful! Hopefully I can tackle this before it becomes a more serious problem. If anyone has any questions please ask and I'll do my best to answer them.