What is the appropriate pressure for car air conditioning pressure testing?
2 Answers
Car air conditioning pressure testing is suitable at around 20 to 30 bar, which should be higher than the working pressure of the car air conditioning. Nitrogen pressurization is generally used for pressurization and leak detection in car air conditioning systems. Car air conditioning refers to the air conditioning device installed in a car, which can cool, heat, ventilate, and purify the air inside the cabin, providing a comfortable environment for passengers, reducing driver fatigue, and improving driving safety. Car air conditioning generally includes refrigeration devices, heating devices, and ventilation devices. This combined system makes full use of the limited space inside the car, with a relatively simple structure and convenient operation.
With decades of car repair experience, I know that typical AC pressure tests show around 30-45 psi for low pressure and 150-300 psi for high pressure, depending on the vehicle model and refrigerant type. For example, R134a usually has 35-40 psi low pressure and 180-250 psi high pressure. Pressure rises when temperatures are high, so avoid direct testing on hot days. Remember to start the engine and set the AC to max before checking gauge readings—if abnormal, inspect for leaks or replace refrigerant. A common rookie mistake is ignoring ambient temperature effects—I've seen cases where 20 psi low pressure was normal in winter but caused issues in summer. Always refer to the vehicle manual or visit a professional shop rather than hastily adjusting and damaging the system. Also, excessively high or low pressure can damage the compressor, which is costly to replace. Regular AC maintenance prevents this—just monitor if the vents blow cold air as a simple self-check method.
