Z-OIL COOLANT Antifreeze is a high-quality ethylene glycol-based organic coolant formulated with special additives that are free of nitrite, amine, and phosphate for use in the cooling systems of gasoline and diesel vehicles for four seasons. High Cooling Performance it lowers the freezing point of the coolant. By raising the boiling point of the water, it prevents the boiling of the radiator water in summer.