To judge the technical condition of the viscous fan clutch, the following two inspection methods are usually used:

(1) when the engine is stopped for a period of time (after the engine is quite cooled), it should be more laborious to pull the fan blade by hand. However, when the engine starts and runs at a medium speed for 1-2min in a cold state, the engine will be shut down again. At this time, it should be easier to pull the blade again. This indicates that the fan clutch is working properly.

(2) thermal state inspection

Start the engine, when the water temperature of the engine is close to 80 ~ 85 ℃, carefully listen to the noise change at the fan of the engine. For example, the noise increases obviously in a few minutes, and the fan speed increases rapidly, so that the engine runs at full speed. When the engine is turned off and the fan blade is pulled by hand, if you feel very laborious, it means that the fan clutch is normal.