What happened when Corolla 1.2t heard the sound of water flowing in the engine compartment at idle speed?

The sound of Pacific car network is common in warm water tank, because it is difficult to make the sound of running water in the internal cooling channel of engine. First, it is difficult to hear the sound of running water when the engine is running. Second, there is basically no air in the internal cooling system of the engine, and the coolant flows beside the cooling system pipeline, so it is difficult to make the sound of running water without the impact of water.

This kind of sound is common in the warm air water tank, because it is difficult for the internal cooling passage of the engine to make the sound of running water. First of all, when the engine is running, it is difficult to hear the sound of running water. Secondly, there is basically no air in the internal cooling system of the engine, and the coolant flows beside the cooling system pipeline, so it is difficult to make the sound of running water without the impact of water. Only when the large cycle is on, you may hear a faint sound in the radiator, but it must be in the state that the thermostat of the hot car is on. If the cold car starts, it is basically a problem with the warm air box, because the warm air box is located under the dashboard, far from the engine and close to the cockpit, and the sound is more obvious. If the cooling liquid is insufficient or the water tank is blocked, a cavity will be formed inside the warm air water tank, and the cooling liquid will make a running sound when it flows through this cavity and hits the wall of the water tank. At this time, you can recall whether you added tap water before. If it has been added, it is likely that the water tank is blocked. This is more troublesome. The heater tank needs to be removed for maintenance. If it is not added, there is basically air in the warm air tank. At this time, you can turn on the warm air, start the engine and exhaust the cooling system.