The cooling system of a car engine typically uses a liquid coolant, such as ethylene glycol or propylene glycol, mixed with water. This coolant is circulated through the engine block and cylinder head, where it absorbs heat from the engine's combustion process.
The heated coolant then flows through a radiator, where it is cooled by airflow from the engine's cooling fan. The cooled coolant then returns to the engine, where it continues to circulate and absorb heat.
