ramarini

i have had my pavillion for about 2years and a half and without any problems. this last months the fan that cools down my laptop has been emitting strange and loud sounds especially after being on the laptop for about 3 hours. i thought that the fan moved off its axis and had that fixed but it didnt help at all. i noticed that the fan starts emitting this strange sounds especially when its works at its highest speed, which happens when i play on this online games (which now a days i cant even play bcz the fan will go berserk after 20min of gaming.) the laptop also emits alot of heat but using the program coretemp the cpu temps seem normal (around 30C). i would like to ask you what the problem could be? i thought it could be a malfunction with the fan and have it replaced or maybe it had something to do with possible dirt in the laptop.

thank you for your help