Question PC makes "rattle" sound

[marv2k]

2 days ago when I booted up my PC normally like every other day it started making a weird rattle noise, like a fan hits a cable but like in a rythm.
So I started to investigate and looked at all the fans and plugged them out to see if the noise stops, but it didn't.
It seems to come from the CPU area tho. My CPU cooler is a liquid cooler so there's no fan. The only thing I did recently was relocating my radiator from the top to the front because I got new RAM and that's also the last time I cleaned my PC, so about 4 weeks ago.
I will include a YT video where you can listen to the sound.

View: https://youtu.be/9czqq8SEIuo


My PC Specs:
MB: Gigabyte Z390 Gaming X
CPU: i7-9700K @ 4.8 GHz
CPU Cooler: Corsair H100i RGB PRO
GPU: Gigabyte GeForce RTX 3070
RAM: G.Skill TridentZ Neo 32GB @ 3600 MHz
1 Sata SSD, 1 HDD and 1 NVME SSD

 

[marv2k]

Update 1: Right after posting this I remembered a video by GamersNexus about AIOs and radiator and stuff. So i just made sure the top of the radiator is above the pump by moving it a bit up. Gonna give my PC a bit to see or hear results.