How to correctly store and test electric fans and clutches from Visco?

Electronic fans and Visco® clutches are characterized by certain specific handling rules, which we discuss in the following article.

In the case of electronically-controlled Visco® clutches, torque is transmitted to the shaft via the fluid used, which translates to practically no wear. The clutch housing includes a working chamber and a supply tank, which is filled with a certain amount of silicone oil. Compared with models with a bimetallic element, an electronic valve controlled by a PWM signal (Pulse Width Modulation) more quickly and precisely regulates the amount of silicone oil that is added to the working chamber. The higher the demand for cooling, the more oil flows into the working chamber, thereby increasing the transmitted torque and, as a result, the speed of the fan.

Correct Storage

Visco® clutches must be transported and stored correctly. Therefore, the upper side is marked on the packaging with up-pointing arrows and the inscription “THIS END UP”. Removed fans and Visco® clutches should always be stored vertically in the mounting position and secured against overturning. Improper storage can lead to oil leakage. This, in turn, can lead to irreversible damage to the clutch.

Visual Inspection and Function Test

The oil in Visco® fans and clutches should not be changed or replenished. If there are traces of oil on the package, do not install these products, as the lack of oil can lead to improper operation or failure of the Visco® clutch.

Electronically controlled Visco® clutches can be tested using a tester and an optical tachometer. For this purpose, reflective markers are attached to the vibration damper and the fan. Then you can accelerate the engine to the rated speed. If the Visco® clutch is not being controlled, the rotational speed will be approximately the same in the case of both markers. On the other hand, if the clutch is constantly controlled it will lead to the closure of the inlet hole in the main disc. Then, the fan’s speed will gradually decrease by significant values.

In case of detection of silicone oil leaks on Visco® clutches and fans, the clutch must be replaced – it is not allowed to refill the missing oil. Ensure the correct position for the duration of transport and storage: dismantled fans and clutches should be stored in the mounting position and secured against overturning.