Why is the Kia Rio heater not hot?

The reason why the Kia Rio heater is not hot is insufficient hot water. The passage into the heating water tank is blocked, resulting in insufficient hot water entering the heating water tank. Insufficient hot water will cause half of the water tank to be hot and half not to be hot, and the wind blowing from the air duct on the cold side will not be hot. The air duct on the non-heating side is not open or blocked. If the air outlet has a switch, check it. The blower fails, causing the damper flap and the damper motor to malfunction. The water temperature sensor signal is faulty.

5. The heater water tank is clogged and needs to be disassembled, cleaned or replaced. The water pump is lost and damaged, and the heater flow valve and coolant circulation valve are damaged. No exhaust after changing coolant.