What are the reasons for a car compressor having normal pressure but not cooling?

[Shannon]

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.

[McHarley]

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.

[LeJune]

Last time my car's AC had the same issue. The refrigerant pressure gauge showed normal readings, but the air blowing out was like a fan. The mechanic said to focus on three key areas: First, the cabin air filter hadn't been replaced for six months and was clogged like a vacuum cleaner bag, resulting in pitifully low airflow from the vents. Second, the condenser - when we removed the front bumper, it was full of dead insects and willow catkins. After cleaning it with a high-pressure washer, the cooling improved immediately. Third, this is where people often get scammed - some shops claim to recharge refrigerant but actually use counterfeit products with incorrect boiling points. The pressure may appear normal, but it doesn't absorb heat at all. Here's an important statistic: over 85% of AC cooling problems are actually heat dissipation issues. When washing your car, remember to gently rinse the condenser with low-pressure water - it's more effective than anything else.

[IsabellaAnn]

It all comes down to energy conversion - the compressor is just a middleman. I once encountered a situation where the AC suddenly stopped cooling while running, but worked fine after restarting the engine. The mechanic used a diagnostic tool to check data flow and found the evaporator coil had frozen, similar to how a refrigerator freezes up. The cause was either a faulty temperature sensor or malfunctioning temperature control circuit, preventing the compressor from shutting off. Another classic case: refrigerant pressure tested fine but cooling performance was poor - turned out to be a mix of R134a and R12 refrigerants, which completely messed up the physical-chemical properties. Nowadays, some cars come with dual-zone AC systems, and if the passenger-side zone damper gets stuck, it can even affect the driver-side cooling performance.