Warning: Keep hands, tools and clothing away from fan blades. To avoid injury, do not start the engine with a damaged fan. Do not attempt to repair a damaged fan impeller - in this case it must be replaced.
Checking functionality
Warning: A damaged fan cannot be repaired. In this case, it is necessary to make a replacement.
1. In the vehicles described, an electric viscous clutch controlled by a PCM microprocessor is used to drive the radiator fan.
2. For safety reasons, it is necessary to remove the key from the ignition switch.
3. Begin the inspection with an inspection. With the engine cold, inspect the fan impeller for cracks or other damage. If such defects are detected, the fan should be replaced.
4. By turning the impeller from side to side, determine the free play of the drive clutch. This value should not exceed 6 mm. If the free play does not comply with the norm, the clutch must be replaced.
5. Make sure that the coupling does not leak and that it is securely tightened to the coolant pump. The leaking coupling must be replaced.
6. Turn the impeller and evaluate the rotation resistance. As the engine cools, resistance increases.
7. Warm up the engine, then turn it off and remove the key from the ignition.
8. Re-evaluate the impeller rotation resistance. When the engine is warm, it should decrease significantly.
9. If this condition is not met, and also in case of jamming of the coupling, it should be replaced.
(The original article is on the website: «ChevyMan.ru»)