What Causes Normal Car AC Pressure but No Cooling?
2 Answers
Reasons for car AC not cooling: 1. Low refrigerant: Car air conditioning typically requires refrigerant recharge every 2-3 years, with some vehicles needing annual top-ups. Even with excellent system sealing, refrigerant can still escape, especially if there are minor leaks in AC lines or condenser. 2. Damaged air blend door: This relatively rare failure occurs when the blend door actuator (usually located in the lower center console area) malfunctions. As the master switch for air vents, its failure means cold air can only leak through gaps. 3. Dirty condenser: During summer when AC performance declines, diagnostic tests may show normal high/low pressure readings. Dealers often recommend radiator/condenser cleaning services, as accumulated spring pollen and debris can cause engine overheating or poor AC performance by blocking heat dissipation. 4. Faulty expansion valve or orifice tube: Malfunctions in these components directly impact AC performance, requiring specialized repair shops for proper diagnosis and service due to their complex nature.
Last time I encountered a situation where the AC pressure was normal but it wasn't cooling, which is quite common. If the compressor is internally worn or not working, the pressure gauge might show normal readings but it's actually not compressing the refrigerant, resulting in no cold air. If the expansion valve is blocked, the refrigerant can't flow, maintaining pressure but with poor cooling performance. Fan issues are also frequent—if the evaporator fan is broken, the airflow is insufficient, and the temperature won't drop, so you might not feel any coolness. Electrical faults, like poor relay contact, can prevent the system from starting the compressor, even though the pressure readings seem fine. I recommend first checking if the fan is running properly, listening for any unusual noises, then inspecting the electrical connections. If necessary, take it to a professional for a check-up—don't tough it out, driving in summer without AC is miserable.
