Question What is this sound?

Mar 24, 2019
Good evening all, hope everyone is having a great weekend!

I was hoping someone could help me out with a sound that is coming from my pc. The youtube video link is below. Over the past week my computer has started having this cycling "grinding" noise, which can be heard about a second into the video and then every 10 seconds or so throughout. It's not constant and doesn't happen at all times when the computer is on, but when it does it happens every 5-10 seconds until some point when it stops. I've tried looking however of course whenever I get the case open it will never happen. Occurs seemingly randomly at different usage levels; just browsing the internet, gaming and everything in-between.

Hopefully one of you heroes can recognize the sound and help me out, it's driving me nuts. Whoever can help out I will owe a beer.