What are the reasons for a car compressor having normal pressure but not cooling?
2 Answers
Car air conditioning compressor working but not cooling is mainly due to lack of refrigerant, damaged air conditioning flaps, dirty condenser, faulty throttle or expansion valve, aging or loose belts, water in the pipelines, etc. There are many reasons for car air conditioning not cooling, such as faulty interior temperature sensors or outdoor temperature sensors. Additional information: Car air conditioning generally requires refrigerant replenishment every 2~3 years, and some cars even need it annually. Even if the air conditioning is tightly sealed, refrigerant can still escape, especially if there are minor leaks in the air conditioning pipelines or condenser. Damage to the air conditioning flap motor is relatively rare, but when it occurs, it can be quite troublesome. The flap motor is usually located in the lower middle part of the dashboard and serves as the main switch for the air conditioning vents. If it fails, it means the switch is broken.
With over 20 years of auto repair experience, I've seen countless cases where the AC compressor pressure is normal but cooling fails. The most common culprit is a clogged evaporator core - when dust coats the fins like a quilt, cold air can't dissipate. Another frequent issue is expansion valve failure, either completely blocked or improperly adjusted, restricting refrigerant flow like clogged blood vessels. Don't overlook the blend door actuator either; if stuck in recirculation mode, it traps hot air inside while blocking fresh air. Also, when the compressor clutch air gap exceeds 0.6mm, it slips - spinning but not transferring power. Last week we had a Mercedes with perfect gauge readings but 30°C vent air - turned out to be a faulty evaporator temp sensor feeding false data to the ECU.
