It's at the front of the engine. Look at the antifreeze indicator. The one with red liquid on it and scales on it.
The function of the automobile warm air box is that the cooling water absorbs the heat in the water jacket, flows into the radiator, then dissipates heat, and then returns to the water jacket, and circulates continuously. The automobile warm air box is mainly composed of radiator core, water pipe, cooling blades, upper water tank and lower water tank. On the radiator, the upper water tank is connected with the water tank below the radiator through a water pipe.