How to Measure Air Conditioning Pressure with a Pressure Gauge?
2 Answers
Pressure gauge measurement method for air conditioning pressure: 1. Inspect and clean the detection joints of the air conditioning system and the high/low pressure connection joints on the air conditioning pressure gauge; 2. Check the air conditioning pressure gauge to ensure both high and low pressure valves are properly closed and all connection joints are securely fastened; 3. Turn off the engine and air conditioning, then connect the high and low pressure hoses of the pressure gauge to the high and low pressure service ports using quick-connect fittings; 4. Start the engine and turn on the air conditioning, then read and record the high and low pressure values; 5. Turn off the air conditioning and engine, then disconnect the pressure gauge from the service ports; 6. Inspect the service ports on the vehicle's air conditioning refrigeration system for any signs of leakage.
Last time my friend's car AC wasn't cooling, we used a pressure gauge to check the AC pressure and ended up covered in dust. First, prepare the pressure gauge and gloves—safety first, as the high-pressure part of the AC system can be dangerous. Start the engine and turn the AC to maximum fan speed and lowest temperature. Locate the low-pressure port in the engine bay, usually a blue metal nozzle, and connect the low-pressure hose of the gauge to it. Remember not to confuse it with the high-pressure port, which is red. Wait a few seconds for the pressure reading to stabilize, then check the dial. Normal pressure on the low side should be around 30 to 50 psi—too high or too low is bad. After testing, turn off the AC and slowly remove the hose to avoid sudden refrigerant leaks. In my case, the pressure was low, indicating insufficient refrigerant, and adding a bit fixed the issue. Remember, beginners should ideally get a helper and not work alone. Also, tools should be calibrated regularly. Regular AC checks can prevent major problems, so you don't end up sweltering while driving.
