PSU "clicking" noise.

I have had my computer build for about a year now and have never experienced this problem. Just recently, about a month or so ago, my computer would make an awful clicking noise. It is as if a fan is hitting something.
I've narrowed it down to the PSU and i have made sure there are no wires close to the openings. An yet it still makes that god awful nose.

I've blown (carefully) air and vacuumed it several times, both of which only stall the noise for about 3-5 minutes. Then it will start back up again at random times.

Anyone know what i could do ?

It is a Thermaltake Toughpower 650W psu. I'm not sure if it is covered under warranty anymore. I bought it off of NewEgg.

I'll try and get a video/sound recording of it with my camera and post it on here.

Could be that the bearings on the fan are shot. My front case fan sounds like it is grinding on something when it is in use because the bearings are shot. My temporary fix was to slide a q-tip through the fan casing to stop the blades from spinning. My temperatures are still at a normal level, but I do plan on purchasing a new fan when I can part with the funds.

I wouldn't recommend doing this with the PSU fan, however.

So i fixed the noise.

I just took out my psu and disassembled it and cleaned the fan, reassembled it and voila. No more irritating noise.

Now i can finally get good sleep at night lawl.

Alright, so about 3 hours after i thought i "fixed" the psu. It started making the noise again.
Granted, it was only for about 2 seconds at a time and there was a very long interval at which it would make noise; it still made noise!

I think i'm going to buy a new psu with my tax returns. *shrug*

If you already took it apart, why don't you just replace the fan with another one?