Coolant : The same thing as antifreeze. This liquid is responsible for keeping your engine cool, keeping the cooling system from rusting and turning into ice in the cold seasons. Coolant has a very low freezing point and a very high boiling point. There are a few variations of coolant as per vehicle manufacturer but they all are designed for the same functions. Coolant comes in colors like green, orange, pink, blue and yellow. When there is a problem on your car with coolant, your car my overheat. Typical signs of a coolant leak will include a color stain liquid leaking from under the vehicle, a sweet burning smell from your engine area or inside the car, a over heating vehicle. Coolant leaks should not be taken lightly and should be inspected and repaired immediately.