A cooling system on a car helps to regulate the engine's temperature and prevent it from overheating. The system does this by circulating coolant through the engine block and radiator. The coolant is typically a mixture of water and antifreeze, which helps to lower the freezing point of the water and raise the boiling point. This allows the coolant to more effectively transfer heat away from the engine. The cooling system also has a fan that helps to circulate air through the radiator, which further helps to dissipate heat away from the engine. Without a properly functioning cooling system, an engine can overheat and suffer severe damage.