What are the common reasons for a car having no warm air but only cold air?
1 Answers
Possible reasons for a car having no warm air but only cold air are as follows: 1. First, determine whether the air conditioning vents are blowing air—whether it's cold air, no air, or air that isn't warm. 2. If there is no air, it may be due to a damaged blower motor or a clogged air filter. 2. If there is air but it isn't warm, it could be due to a faulty blend door actuator or a stuck air flap. Below are the steps to diagnose why the warm air isn't heating: 1. First, check whether the engine coolant temperature is normal. If it remains at a low temperature and doesn't reach the operating temperature, the warm air will definitely not be hot. In this case, focus on checking whether the thermostat is stuck in the open position or whether the coolant temperature sensor signal is accurate. Repair or replace the faulty component as needed. 2. Pay attention to whether there is a significant temperature difference between the inlet and outlet hoses of the heater core. If such a difference exists, it is certain that the heater core is clogged and needs to be disassembled, cleaned, or replaced. 3. Check whether the coolant flow rate and temperature entering the heater core meet the requirements. Temperature differences can be measured using an infrared thermometer, while flow conditions can be assessed through diagnostic data and fault logs from a scan tool. Common issues include a faulty water pump or damaged heater flow valve and coolant circulation valve. 4. Check whether there is air trapped in the cooling system. A common cause is failing to bleed the system after replacing the coolant. A more unusual cause could be a damaged cylinder head gasket. Use standard coolant bleeding methods to confirm further.
