What is the normal pressure value for car air conditioning?
3 Answers
Under normal operating conditions of the air conditioning system, the low pressure typically ranges between 1.0-2.5 bar, while the high pressure ranges between 15-18 bar. Below are specific details about car air conditioning pressure values: 1. The normal range for car air conditioning pressure detection is generally that the high pressure should not exceed 1.7 MPa or be lower than 1.3 MPa. 2. The normal range for low pressure is generally not lower than 1.15 MPa and not higher than 1.25 MPa. If the low pressure is higher or lower than this normal range, it indicates abnormal expansion valve adjustment. 3. The air conditioning gauge usually has two dials: a blue one for low pressure and a red one for high pressure. If the ambient temperature is higher, the pressure should be slightly higher, and if the ambient temperature is lower, the low pressure should also be appropriately lower.
I remember the mechanic at the repair shop mentioned last time that AC pressure depends on specific operating conditions. During normal operation, the low-pressure side is generally 1.5 to 2.5 kg/cm², while the high-pressure side is around 13 to 16 kg. However, in summer traffic jams with high temperatures, it's normal for the high pressure to spike to 18 kg as long as the compressor keeps running. If the low pressure drops below 1.2 kg, it might indicate refrigerant shortage, and you'll notice weaker cooling when the AC is on. The worst scenario is when high pressure exceeds 20 kg, which could mean poor condenser heat dissipation or air mixed in the system. Mechanics need specialized gauges to measure it accurately.
Last year, the AC in my old car stopped cooling. At the 4S shop, they found abnormal pressure readings. The technical manager explained that pressure isn't a fixed value - it depends on ambient temperature and refrigerant type. Most vehicles today use R134a refrigerant, where at 35℃ the low pressure should be around 2.0bar and high pressure about 15bar. I saw the mechanic pop the hood last time, connecting that yellow-blue dual-gauge tester to the AC lines - the needle showed only 0.8bar on the low side, clearly indicating refrigerant leakage. They recommend AC system checks every two years, especially paying attention to pressure tests for vehicles over five years old.
