Case fan making weird clicking noise

[Alessandroperch]

Anyone know why one of my case fan is making this weird loud clicking noise? This usually happens every morning after my pc has not been turned on for about 9-13 hours. What happens is my computer starts , the Bios screen exits then it immediately starts making a clicking noise and continues for about a minute before it disappears on its own. Any ideas whats wrong ?

 

[Techneer Jai]

Are you certain it is the case fan? A clicking sound is generally caused by a switching power supply (like a computer PSU) struggling under load.
If it is indeed a specific fan, you need to first check for clearance issues between the fan blades and the support mechanicals or for a bit of random debris that gets blown aside as the fan comes up to speed but returns to a resting spot by the blades when they stop spinning.
If the sound gets louder over time and / or begins or becomes a rumbling sound it means the bearings are failing and you need a replacement fan.

 

[Alessandroperch]

Yes I am positive it is the case fan. I have tested the PSU and it is not making any noises.

 

[Techneer Jai]

OK, here is how you determine what the problem is.
First, preferably before you power up the computer for the first time that day, unplug everything from it and carefully open up the case.
Slowly unmount the case fan and watch carefully for any tiny objects falling out as you do.
Assuming that nothing falls out, set the suspected fan on a piece of cardboard and temporarily plug in and power up the computer to see if the sound repeats itself.
If it does, examine the fan closely and see if you can determine if there is a physical reason for the sound.
If no sound, there is probably a nearby wire that was partially obstructing the fan and causing the sound you describe, or a small piece of debris that fell out unobserved as you were removing the fan.
If it still makes the sound and you can not determine a physical cause for it, then a bearing is going bad and you need to replace the fan. Same thing if the fan makes the sound but it dies away as you watch it operate. Bad bearing.