Coolants are substances used to regulate temperature in various systems, primarily in engines and industrial machinery. They absorb heat and help maintain optimal operating temperatures, preventing overheating and ensuring efficient performance. Common types of coolants include water, antifreeze, and specialized chemical mixtures designed for specific applications. In automotive engines, coolants circulate through the engine block and radiator, transferring heat away from critical components. This process is essential for maintaining engine efficiency and longevity. Additionally, coolants are used in other systems, such as HVAC units and nuclear reactors, where temperature control is crucial for safety and functionality.