Contents: Magnetic clutch ↡ Viscous coupling ↡
Magnetic clutch
Cross section of a fan magnetic clutch
1 - primary disk; 2 - hysteresis disk; 3 - secondary disk; 4 - permanent magnet; 5 - steel disk; 6 - ball bearing
1. With the engine stopped, rotate the fan manually and make sure it rotates smoothly and quietly.
2. Replace the fan clutch if it does not rotate or is noisy.
Viscous coupling
Cross section of a viscous fan clutch
1 - clutch housing (secondary part); 2 - leading disk (primary part); 3 - shaft with flange; 4 - seal; 5 - needle bearing; 6 - cooling fins; 7 - oil scraper; 8 - spring; 9 - thrust finger; 10 - bimetallic plate; 11 - lid with holder; 12 - intermediate washer; 13 - Falling hole; 14 - valve lever; 15 - reservoir; 16 - working chamber
1. Warm up the engine to normal operating temperature and maintain its speed between 4000 and 4500 rpm. Do not cover the radiator, otherwise the clutch will not respond correctly to temperature changes.
2. Using a thermometer (temperature indicator) make sure that when the engine heats up to 90-95°C, the fan speed increases by about 1000 rpm. If the clutch is working properly, this will be noticeable by ear. A faulty clutch should be replaced.