What is the primary composition of engine coolant?

The primary composition of engine coolant is indeed a mixture of water and antifreeze. This combination is vital for several reasons. Water acts as a heat transfer fluid that absorbs heat from the engine, effectively preventing overheating. Antifreeze, typically made from ethylene glycol or propylene glycol, lowers the freezing point of the coolant, which is essential for preventing the coolant from freezing in cold temperatures. It also raises the boiling point to help maintain effective cooling even in high-temperature conditions.

Additionally, antifreeze includes corrosion inhibitors that protect the engine and cooling system from rust and corrosion. This balanced composition ensures that the coolant performs effectively under various operating conditions, making it essential for a well-functioning engine.