What are the reasons for no hot air in the car?
3 Answers
Reasons for no hot air in the car: 1. Engine thermostat failure; 2. Hot water valve or hot water valve vacuum actuator failure; 3. Heater inlet or outlet pipe blockage or heater core clogged with dirt; 4. Temperature control damper or control cable damage; 5. Air conditioning blower damage or blower control circuit failure; 6. Air conditioning air distribution pipe blockage or air leakage. Car heating equipment is divided into non-independent heating systems and independent heating systems according to the heat source used. Non-independent heating systems use the residual heat of car exhaust or engine cooling circulating water as the heat source and introduce it into a heat exchanger. The fan blows the air inside or outside the car through the heat exchanger to heat it up. Independent heating systems are generally composed of a combustion chamber, heat exchanger, fuel supply system, air supply system, and control system.
Last time my car had no hot air, the problem was due to the engine cooling system not performing well. It could be due to insufficient or dirty coolant, or a leaking radiator; if the thermostat is stuck in the open position, the engine temperature won't rise, resulting in no hot air; the heater core might be rusted and clogged, blocking internal passages; or the temperature control valve might be malfunctioning, making the temperature knob unresponsive. I used a thermometer to measure the air vent and knew it was a big deal when it was ice cold. For routine maintenance, change the coolant every two years to prevent clogging. In winter, no hot air can lead to foggy windows, which is very dangerous as it blurs vision. Don't push through it—go to the repair shop for a comprehensive check-up. Replacing parts won't cost much, and safety comes first.
When encountering no hot air in the car, I pondered for a long time to find the cause. The most common reasons are incorrect AC settings—check if the mode is set to cold air; coolant level too low, preventing the engine from heating up; or a faulty blower that doesn't blow air, just making a humming sound without airflow. If you want to DIY, pop the hood to check the coolant level and try adjusting the temperature knob to see changes. If that doesn't work, call a professional technician—don't skimp on the inspection fee. Driving without heating in winter can freeze your hands and feet and affect defogging, increasing accident risks. During regular oil changes, have the AC system checked to nip problems in the bud.
