Coolant is an engineered fluid belongs to a family of other automobile fluids like brake oil, Steering fluids etc with anti-freezing agent usually florescent green in color.
Coolant draws heat away from hot engine parts to prevent over heating during use.
Coolant, as the name implies is to prevent freezing of the coolant when the vehicle is unused in cold climates.
Coolant inhibits corrosion of the metal components of the cooling system and engine block.
NOTE: For best results dilute 25 part of basil coolant with 75 part of Basil Radiator water.