I have a strange thing going on with my fan, she keeps making a loud noise despite the laptop is cool.

What is even stranger is when i play a game, the laptop become hotter of course and the fan start turning with high speed but with a normal noise, it almost disappears after 15min gaming or so..
and when i close the game the laptop starts to cool down and the fan starts to be loud.
btw, i opened the laptop, and i cleaned the every component, i disassembled the fan and cleaned it, it wasn't that dirty since the laptop is almost two years old, but i didn't renew the thermal paste in the cpu or the graphic card. but i dont think that matters since the laptop is cool when the fan is being noisy.