Noisy EEPC fan

I have an Asus Eee Box PC 1033 connected to my TV via HDMI and it runs Kodi. Even though I do clean this mini PC regularly, it was making a loud hum since the last couple of days. Thinking it might be getting too hot, I checked the temperature using sensors command it showed normal temperatures.

~$ sensors
coretemp-isa-0000
Adapter: ISA adapter
Core 0:       +49.0°C  (crit = +100.0°C)
Core 1:       +49.0°C  (crit = +100.0°C)

Then I opened up the cover and booted it. Right from the start, the hum was there and as temperature doesn't go up that fast, I focused on the heat sink and cooling fan assembly. I unscrewed the 7 screws (2 each for heat source of the heat-sink, and 3 for fan housing). The fan was a DC Brushless Model KSB0505HB - found in many laptops. After removing the cover on the fan and removing the rotating blades, all that was required was cleaning the axle of the blades and adding some lubrication to it. 

Closed up the fan cover, and screwed the heat sink and fan assembly back in its place. After booting the PC, the hum of the fan was back to normal levels and temperatures were a bit down too as I took the opportunity to put some new thermal paste on CPU and GPU chip.

In case you want to do similar job to your PC fans, a quick YouTube search and review of those videos will help you.