OK problem is that the exhaust fan I have fitted behind the radiator of my water cooling system is not working properly. It's still spinning but at but at a totally useless speed and making an 'unhealthy fan noise'. I tried removing the radiator to get at the fan, giving it a prod blowing all the dust off it etc... When I screwed everything back in again and restarted my system the fan apparently worked fine and my CPU temperature came back down to a normal level. However given about 30-60mins and it was acting up again. I tried this a few times and it has worked temporarily for about the same period of time. It's not really a long term solution though... I also tried unplugging it from the motherboard and then plugging it back in but this made no difference. Does this sound like the Fan itself is at fault or something to do with the connecting electronics? If anyone has any ideas on how to fix it before I get on the phone to order a replacement fan that would be great. Also I'm going to get off the computer now and let it cool down while I wait for a reply.