What are the reasons for low coolant temperature?

[Jasper]

The reasons for low coolant temperature are: 1. Faulty water temperature gauge and wiring; 2. Damaged water temperature sensor; 3. Thermostat valve stuck open; 4. Louvers unable to close; 5. Faulty temperature control switch or fan motor wiring; 6. Malfunctioning silicone oil clutch in vehicles equipped with silicone oil clutch fans. The functions of coolant are: 1. To prevent freezing and expansion of coolant in cold seasons, which could crack the radiator and damage the engine cylinder block; 2. To prevent corrosion of metal parts and aging of rubber components; 3. To reduce scale formation, avoiding blockage of circulation pipes and affecting the cooling system's heat dissipation function; 4. To prevent the engine from overheating, ensuring it operates at the proper working temperature; 5. To provide lubrication for the water pump, thermostat, and other components.