Why is there a sound of water flowing in the hot water tank of a car?

There are many reasons for the sound of water flowing in the water tank of automobile heater, as follows: 1. There is air in the pipeline or the heater is blocked. In this case, you need to go to the 4S shop for inspection and maintenance according to the situation. 2. Heat the water tank and let the coolant circulate in the car. This is normal. If there is no water leakage, there is no problem with the heating. 3. Insufficient coolant. Need to replenish coolant in time. When filling antifreeze, please don't do it when the engine is overheated; Otherwise, if you open the lid of the antifreeze tank, you may get burned. Try not to mix antifreeze, because different antifreeze costs are different; The antifreeze does not need to be mixed with water unless it is concentrated antifreeze.