Why does the car heater blow the antifreeze in the water tank into the interior of the car?

It may be that the radiator in the engine room is corroded, resulting in water leakage, or the connector of the indoor radiator is loose, and the leaked liquid is blown out by the air conditioning fan.

Generally speaking, the engine water tank has two radiators. A radiator is located in the front of the vehicle and has a large area. When the vehicle is running, there will be airflow to take away the heat, and the heat generated by the engine is mainly dissipated through this radiator. The other radiator is located in the center console of the cab. If hot air is needed, the air conditioner fan will push the air flow through the radiator, and the air flow will be heated and blown out from the air outlet. If the indoor radiator leaks water, the leaked liquid will be blown out with the airflow.