The growl of the PSU cooler. What could be?

Question

Iron

The new system unit worked for two years in the office,
now the power supply fan growls at startup,
stops after 20 minutes ,
or if you tap on the grate in front of the blades (three clicks of your finger),
then it stops.
It can be just dust - blow it out and that's it.
Or do you still need an oil change or a cooler replacement?
Like an unbalanced
little shake when spinning and like a growl sound

Answer 1

The lubricant has rubbed off.
Lubricate, preferably with silicone oil.
Google is full of instructions.

Answer 2

I'm not an expert, but I think machine oil should help here: unwind the PSU, carefully remove the label from the top of the cooler, pour a couple of drops of oil into the cooler, scroll lightly, stick the label back, for reliability, you can fix it with tape. You twist everything back. PROFIT.

Answer 3

Nothing will help the fan, no disassembly-lubrication - it's all for a short time and just a waste of time in an attempt to save on matches. The fan must only be replaced.