Laptop fan is different from desktop one. General desktop fan rotates in high speed once you push the “Power” button; while laptop fan is an exception, generally only when temperature reaches BIOS preconcerted limit, the fan begins to run, usually not in full speed, and it has some ranges to select to run. This is concerned for power saving and noise issue. Generally, because of a long period of working, second hand laptop’s fan has lots of dust and dirt inside. When the fan starts to work, as the block of dust, the noise would be really loud. Even sometimes the dirt sticks on fan leaf, which blocks normal working. And this is really dangerous. As there’s no criterion in this field, and every model of laptop has different internal structures, it is not practical to change new fan for laptop.
So now, the simplest way is to clear the fan yourself. And step is to dip some alcohol with clean cotton, then to clean every leaf of the fan and the central place of the rotating axis. Notice that don’t add any lubricant to the rotating axis of the fan, as the fan is different from normal desktop one, which is a top grade fan lubricating itself automatically. Not like common ball bearing fan, lubricant won’t take any effect, but to affect normal running of the fan.
Dust and dirt should be cleared out; we still need to think about the problem of deformation caused by heat. As fan rotates in high speed for a long time, it blows hot wind to radiate the heat, so the plastic leaf will gradually deform. I have already mentioned above, it is not possible to change new fan.
So we can consider about to cut off the deformed part of the leaf properly, by this way, we can lower the noise caused by asymmetric rotating leaves.