* Cooling: It prevents the engine from overheating. Water alone boils at a much lower temperature than the engine can reach under normal operation, leading to catastrophic engine damage.
* Freezing protection: In colder climates, water in the engine block will freeze, expanding and potentially cracking the engine block, radiator, or other components. Antifreeze lowers the freezing point of the water.
While your car *might* briefly run without antifreeze in warm weather, it's extremely risky and will likely lead to engine failure. Never operate a vehicle without coolant.
