Is the inlet pipe and outlet pipe of warm air small water tank cold normally?

If the temperature difference is large, it means that the coolant entering the water tank is not circulating, and it is estimated that the warm air of the car will not work. If you usually fill the car coolant with tap water, it is likely to produce scale and block the small water tank. At this time, compressed air should be used for dredging. The temperature difference between the inlet pipe and the outlet pipe should not be obvious.