What Are the Reasons for No Hot Air from the AC After the Water Temperature Reaches 90 Degrees?

[LaKing]

After the water temperature reaches 90 degrees, the reasons for no hot air from the AC include thermostat issues, water pump circulation problems, and airlocks in the cooling system. Thermostat Issues: Whether the thermostat is stuck open or closed, it can cause heating malfunctions. A thermostat stuck closed will prevent proper coolant circulation, leading to excessively high water temperature. If stuck open, the water temperature gauge will always read below 90 degrees, resulting in slightly warm air at idle but no heat at high speeds. Pay attention to the thermostat's operation. Water Pump Circulation Problems: Poor water pump circulation directly causes high water temperatures. Replacing the water pump will naturally resolve the heating issue. Airlocks in the Cooling System: An airlock in the engine's cooling system disrupts the normal operation of the car's coolant circulation, leading to no hot air. If the heater core's inlet pipe is hot but the outlet pipe is cold, it indicates a blockage in the heater core, which needs replacement.