If You Don’t Discharge The Caps Properly, The Hospital May Never Discharge You!
Seriously, before even thinking about touching the insides of your PSU make sure those capacitors don’t have any charge left in them or this might be the last thing you ever do. If you are unsure about how to accomplish that safely then here is an article on ways to do it and problems to look for, and one from about the time the PSU Hardware Asylum is working on was released. Once you’ve managed that, you can safely introduce your fingers to the inside of the enclosure and take a look at the fan which is installed.
The whole purpose of opening the PSU is to replace an old, or poor quality fan with a new Noctua fan that will both cool better and run significantly more quietly. They chose a Noctua Redux industrial 80mm fan, with a third wire for RPM sensing. The old PSU they were upgrading lacked that ability and so they carefully removed that third wire; please do the same as you don’t want dangling wires in your PSU!
If you have a PSU that is making far too much noise, Hardware Asylum provided a video tutorial on removing the old fan and installing a Noctua fan here.
In full disclosure, I did replace the fan twice in this PSU. The first replacement was a cheap two wire fan from Amazon and after getting it installed, I discovered that it was even louder than the fan I took out so, I decided to fix the situation correctly.