Fan Clutch Tutorial - Part 1 What is a Fan Clutch and How Does it Work? The fan clutch is a coupling between the water pump shaft and the fan that allows the fan to be operational at low speeds and disconnected at higher speeds. The fan clutch is important, because it allows the engine to operate more efficiently by removing the load that the fan places on it, and cools the engine when cooling is needed. There are two types of fan clutches and both operate on the fluid-drive principle: ff It is important to note that since the fan clutch and water pump share a common shaft, the operation of one will affect the operation of the other. If the bearing in the fan clutch wears out then the fan will wobble. The vibration from the wobbling fan blade will be transmitted to the water pump bearing which will cause it to wear out quickly. On the other side of the coin, a worn water pump bearing will cause the bearing in the fan clutch to wear out (again, due to the transmitted vibrations). If this water pump is replaced without replacing the fan clutch, then the worn fan clutch will cause the new water pump to fail. That is why it is very important that the water pump and fan clutch be replaced together.  'A' shows a failed bearing, while 'B' shows a silicone fluid leak. Next - Fan Clutch Tutorial - Part 2