2. The heater water tank is damaged: the heater water tank is damaged or leaked. Check whether the heater water tank is damaged or leaked, and repair or replace it in time when problems are found.
3. Water pump leakage: Water pump is one of the core components of antifreeze circulation system. Leakage of water pump will also lead to the reduction of antifreeze. Check whether the water pump leaks, and repair or replace it in time when problems are found.