What is the method for testing the pressure of a car air conditioner?
3 Answers
Car air conditioner pressure testing method is to use an air conditioner pressure test gauge, connecting the blue tube to the low-pressure thick pipe and the red tube to the high-pressure thin pipe for testing. Functions of car air conditioner: 1. Achieve cooling effect by continuously changing the state of refrigerant in a cycle; 2. Remove dust, odors, smoke, and toxic gases from the air inside the car, making the air inside the car fresh, and humidify the air inside the car to increase the relative humidity of the air inside the car. Functions of car air filter: 1. Ensure the air filter fits tightly against the housing to prevent unfiltered air from entering the compartment; 2. Separate dust, pollen, grinding particles, and other solid impurities from the air; 3. Adsorb moisture, soot, ozone, odors, carbon oxides, carbon dioxide, and sulfur dioxide from the air.
Testing car AC pressure is actually quite simple, and I often do it myself because I love tinkering with cars. First, you need to locate the two ports of the AC system: the high-pressure port, usually near the compressor, and the low-pressure port, located near the evaporator. When connecting the pressure gauge, make sure the car engine is running and the AC is set to maximum cooling. First, connect to the low-pressure port and read the value—normal range is between 25 to 45 psi. Then, connect to the high-pressure port, which should be controlled within 150 to 250 psi to be considered safe. If the pressure is too high or too low, it could indicate insufficient refrigerant, a leak, or a compressor issue. After testing, remember to close the valves and slowly remove the gauge to avoid refrigerant spray injuries. I recommend checking before the peak of summer; otherwise, if the AC fails during a long trip, it can be unbearably hot. Testing every six months can save you a lot of money in the long run.
When measuring car AC pressure, safety is the top priority. I must remind you to wear gloves and goggles before operation, as refrigerant leaks are no joke. The steps are: start the engine and turn on the AC, locate the low-pressure port to connect the gauge and read the pressure, with the low side around 25-45 psi; then check the high-pressure port, which should be around 150-250 psi. In abnormal situations like low pressure, don’t rush to add refrigerant—it could indicate a leak or blockage; if the pressure is too high, check if the radiator is dirty. Pressure testing can also help diagnose cooling issues, such as fluctuating needles indicating compressor failure. Repair shops usually run a complete diagnostic process to avoid rework risks. Regular maintenance checks like this can extend the lifespan of your AC system.
