What are the reasons for high car coolant temperature?

[Grady]

Reasons for high car coolant temperature: 1. Insufficient coolant - coolant leakage or low coolant level can cause engine temperature to rise; 2. Cooling fan malfunction - when the vehicle runs at high RPM, heat cannot be effectively transferred to the antifreeze, affecting heat dissipation and leading to increased antifreeze temperature or boiling; 3. Water pump circulation failure - including seized bearings or damaged impeller, which slows down coolant circulation and easily causes engine overheating; 4. Thermostat malfunction - the car's cooling system may fail to perform major circulation, resulting in increased coolant temperature; 5. Poor radiator heat dissipation - prolonged use of water as medium can cause rust buildup in the engine and radiator, leading to poor heat dissipation and high coolant temperature.