Coolant is a fluid used in engines and machinery to regulate temperature and prevent overheating. It absorbs heat generated during operation and circulates through the system, transferring heat away from critical components. Common types of coolant include water, antifreeze, and specialized chemical mixtures. In automotive applications, coolant is essential for maintaining optimal engine performance and longevity. It helps protect against corrosion and freezing, ensuring that the engine operates efficiently. Regular maintenance, such as checking coolant levels and replacing old coolant, is important for the health of the vehicle's engine.