So just to be fair this is NOT a Debian specific issue as I run several distros including Debian and Windows10. I have a recently built DIY computer that is making a LOUD squealing sound. I thought of fan bearings at first and I tried individually stopping each fan to see if the noise stopped one was bad on the Enermax 360 cooler so I replaced it. That seemed to get rid of the issue, but after about 2 weeks it returned even louder. I checked every fan but none were the culprit. I have checked the graphics card fans also and they are fine. This only seems to leave the Enermax liquid cooler as a possible issue.
I have been on this list for MANY years and have an idea that someone here may have had similar issues. If so, please advise as to your solution, especially if the way it is mounted is of concern. Mine is mounted vertically with the tubes at the top going to the CPU mounting block. This is on a Ryzen 1950 CPU so I must have a high capacity cooler.
Thanks!!
John
Squealing issue in a liquid cooler sounds like you might have an air bubble someplace you shouldn't?
HTH.