For more than 30 years, SACHS has been providing intelligent fan clutches for nearly every vehicle model. They are located in the vehicle directly behind the radiator. In this way they can check the current cooling requirements and draw in additional air through the radiator if necessary.
The center of the SACHS viscous clutch for passenger cars consists of light-alloy multidisks, which generate the largest possible surface area. There is a bimetallic spring on this surface. If the radiator becomes too hot, this surface heats up, including the spring. The bimetallic spring opens a valve, ensuring that viscous liquid is pumped into the working chamber. This makes it possible to adjust the speed of the fan or the fan impeller as required. If the radiator temperature drops again, the bimetallic spring closes the valve, ensuring that the viscous liquid is pumped out of the working chamber and that the fan or the fan impeller is reduced to the speed required for the temperature.