What Are the Reasons for the Car Heater Not Being Hot?

[DeAlexa]

The reasons for the car heater not being hot are: 1. The thermostat is constantly open or opens too early, causing the cooling system to circulate in a large loop, resulting in low external temperature; 2. The water pump impeller is damaged or slipping, leading to insufficient flow through the heater core and low heat output; 3. There is an airlock in the engine cooling system, causing poor circulation and resulting in high water temperature but no heat from the heater. The solutions for the car heater not being hot are: 1. Replace the water pump impeller; 2. Clean and unclog the engine cooling system; 3. Install or replace the thermostat. The principle of the car heater is that during heating, the high-temperature coolant from the engine flows through the heater core, and the air blown by the blower also passes through the heater core, allowing warm air to be blown out from the car's air vents.