In winter, the water temperature of diesel vehicles rises slowly and drops quickly. If there is nothing wrong with the thermostat and heater switch (the heater switch of some cars is electrically controlled, which is difficult to open), the indoor adjusting lever and handle are normal, and the circulation of the water pump and water tank is normal. Then install a shutter at the air inlet of the water tank in front of the car, so that you can unconditionally block the water tank with sacks or something, and then remove the sacks according to the temperature, so that the temperature will rise quickly, but you have to keep.