either something is stuck in it restricting free movement or the ball bearing is breaking/leaked it's lubricant... you need to find an appropriate replacement. what model closed loop cooler is that? should be able to find an exact or similar replacement online, unscrew the radiator, take the fan off and unplug it, and put the new one in it's plug/place. its a very easy task, just make sure you dont have the power unit plugged in and touch metal on the case to discharge any static electricity. if you zap a ROM chip on the board you could accidentally wipe it's memory and brick the motherboard. dont touch chips willy nilly especially if youre on carpet.