Normal phenomenon, don't worry, you can use it with confidence. You can use the diagnostic computer to check whether the thermostat water temperature sensor in the engine control module is faulty. If there is, it is an electronic thermostat. If there is no fault, it is normal.
Introduction:
In winter, heating warm air will continue to consume heat from the engine. If the displacement of the engine is small, the heat generated by the engine operation will not be enough to offset the heat consumed by heating the warm air. Turning on warm air will more easily lead to a rapid drop in water temperature. Of course, it is normal for the water temperature to drop.
When driving in cold weather, you can wait until the whole car heats up, preferably 90 degrees, and then turn on the warm air after driving for a certain distance, so that the water temperature will generally become normal and the engine will be better protected.
Remember not to sleep in the car when the warm air is turned on, because the gas in the car is replaced by the air conditioner when the car is driving, and the carbon monoxide generated when the engine is stopped enters the car, which is easy to cause carbon monoxide poisoning in a closed car.