Cooling System: Testing and Inspection

Fig. 1 Cooling Fan & Thermo Switch Installation:

1. Start engine and run until it reaches normal operating temperature.
2. Monitor coolant temperature using suitable thermometer and observe cooling fan operation.
3. Cooling fan should begin to operate when coolant temperature reaches 196-200°F, and fan should stop running when coolant temperature drops to 187-191°F.
4. If fan fails to operate, stop engine, disconnect electrical connector to thermo switch, Fig. 1, connect suitable jumper between connector terminals, then turn on ignition switch.
5. If fan operates, replace thermo switch and recheck system operation.
6. If fan fails to operate, check for blown fuse, damaged or disconnected wiring or defective fan motor.