CPU Fan Failure By | March 6, 2022 0 Comment The CPU fan in a small desktop PC had failed and was causing a thermal shutdown. This happens when the CPU temperature exceeds a certain level and is done to prevent damage to the CPU through excessive overheating. When replacing a CPU fan it’s generally a good time to also replace the thermal paste. Thermal paste is a semi-viscous compound, that’s applied between the CPU and the metal heatsink. This allows the transfer of heat between the top of the CPU and the metal heatsink that sits between the Fan and the CPU.