Computer fan is constantly noisy. How do I diagnose?

m1ndkiller

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Sep 27, 2011
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One of my PC fans suddenly started making a constant sound while it's running. It's a stock Antec exhaust fan that came with my case. My first suspect was that it was hitting a cable, but I double-checked and that isn't the case.

I even tried spinning all of my fans with my hands, and none of them made a sound, so it must be something with the mechanism that the computer uses to make the fan spin.

I also tried both loosening and tightening the external screws that hold the fan in place inside the case, but it didn't make a difference.

So, I have a couple of questions:
1) is it likely that the fan is broken somehow, or do I just need to tighten something on the fan itself?
2) is it safe to unplug the fan for now? I have 3 intake fans and 2 exhaust fans, so I was worried that removing one exhaust fan might mess up the balance.