Fluid Fan Drive: Notes

Fluid coupling filled with silicone oil attached to water pump pulley at input side and to fan at output side. A bi-metal strip on front of clutch moves out under higher temperatures and allows metal rod in center of clutch to move out. This rod actuates a valve inside clutch to control amount of fluid admitted to coupling from a reserve chamber. This action increases fan speed when air becomes hotter. Reverse action takes place under colder temperatures.