1. Boiling Point: Antifreeze raises the boiling point of the coolant mixture, preventing it from boiling over and creating pressure in the cooling system. This is especially important in hot climates or during heavy engine loads.

2. Freezing Point: Antifreeze lowers the freezing point of the coolant mixture, preventing it from freezing and potentially damaging the engine block in cold climates.

It's worth noting that antifreeze also acts as a corrosion inhibitor, protecting the engine's metal parts from rust and other damage.