My rear PC fan recently started making a ticking/clicking noise. It usually happens when I’m gaming or running demanding programs. When I’m just on the desktop, it’s mostly quiet, although even after I close a game it can keep ticking for a few more minutes before stopping.

What could be causing this? Does this usually mean the fan needs to be replaced, or is there something I can try first? I already tried blowing the fan out with compressed air, but it didn’t help.

Also, if I do need to replace it, can I safely use my PC without the rear exhaust fan for a few days until a new one arrives? I still have 3 front intake fans in the case, so airflow wouldn’t be completely gone.