Will the Fan Run if the Thermostat is Broken?

[MacBennett]

The thermostat controls the operation of the cooling fan. If the thermostat is broken, it cannot control the fan. Methods to determine if the thermostat is functioning properly: 1. Inspection after starting the engine: Open the filler cap of the cooling water tank and observe if there is any water flow inside. If there is no flow, it indicates that the thermostat is damaged or there is debris stuck between the main valve and its switch. 2. Judging by feeling the temperature of the upper and lower radiator hoses: Start the engine and after 3 minutes, touch the upper and lower hoses. If the thermostat is working properly, the temperatures of the upper and lower hoses will differ—generally, the upper hose will be hot while the lower one will be cool. When the engine coolant temperature reaches 90°C, both hoses should become hot, indicating the thermostat is functioning correctly. If the temperatures of the upper and lower hoses remain the same after starting the engine, the thermostat is not working properly.