Question Problem with my rear fan

[Fowllwo]

When I start my PC my rear fan makes a weird noise and it doesn't push air out. When I tap it with my finger 2 or 3 times(I tap the rear cover/grille) it stops making the noise and starts working normally. Any ideas what could it be and is it critical. Oh and also my rear fan is NZXT which comes with the NZXT S340.

 

[Phillip Corcoran]

Fan could be choked up with dust. Turn off PC and try blasting off dust with air-duster.

 

[jexorz]

I had this exact problem with one of my front fans, Sounded like a blender until stopped it with my finger and let it start back up again. I think this happens when the bearings have worn slightly and are allowed to vibrate. I would replce the fan. They're incerdibly cheap and fairly simple to swap out.