Antifreeze has several important functions. Firstly, it prevents the coolant from freezing in the cooling system during the winter, which can lead to serious damage. Secondly, it protects the engine from overheating, which can also cause breakdowns. The process of replacing antifreeze includes draining the old solution, flushing the system, and filling it with new antifreeze. It is important to use the same type of antifreeze recommended by the car manufacturer to ensure optimal operation of the cooling system.