I want to give a big shout-out to the online retailer The Peaceful Outcome (TPO) and their PS2 Noctua upgrade kit. If you have a PS2 with a loud fan, then this kit is perfect.
Backstory: I have owned my PS2 since Christmas 2001. The entire time the fan in the system was loud. I always assumed that was normal since I had never really listed to another PS2 in a quiet setting. Fast forward to 2019, and while walking in my neighborhood, I found a PS2 in a box that was sat out on the street for junk pickup. It was a later revision fat PS2 that lacked the firewire port. I grabbed the unit, took it home, and discovered there were no significant issues. I was surprised to learn the system was virtually silent when compared to my PS2.
Recently I was playing through the original Final Fantasy XII, and the noise of the PS2 finally got to me. Other members of the RetroRGB Discord server had talked about the fan upgrade, so I went to eBay and bought one for myself. I felt $35 for the Noctua fan, fan guard, 3d printed rear panel parts, and wiring pigtail more than reasonable, and the results were impressive. The installation took less than one hour, and my PS2 is now completely silent. Check out the before and after.
For instructions on removing the original fan from a PS2, I recommend following the guide posted at iFixit.com. The process involves completely removing the PS2 mainboard from the bottom shell to get the fan unplugged from its header.
Links to the TPO’s Amazon and eBay listing are below (these are not affiliate links).