What are the steps for adding refrigerant to a car's air conditioning system?

[DeHope]

The steps for adding refrigerant to a car's air conditioning system are: 1. After evacuating the system, close the high and low pressure manual valves on the manifold gauge set; 2. Connect one end of the middle hose to the refrigerant can tap valve, open the refrigerant can valve, then loosen the nut on the manifold gauge hose to allow gas to escape for a few minutes before tightening it; 3. Open the high-pressure side manual valve and inject the specified amount of liquid refrigerant. After completing the refrigerant charging, close the manual valves on the manifold gauge set and the tap valve on the refrigerant can, stop the engine, and quickly remove the manifold gauge set from the compressor to avoid excessive refrigerant leakage.

[SanCourtney]

I'm quite familiar with car AC refrigerant recharge! You'll need to prepare a manifold gauge set and refrigerant. First, start the car and turn the AC to maximum, then connect the high and low pressure hoses—remember to connect the blue gauge to the low pressure port and the red one to the high pressure port. Check the pressure gauge readings at this point; if the low pressure is below 25 psi, it means the refrigerant is low. Then invert the refrigerant can and slowly open the valve, listening for the hissing sound as the refrigerant flows in. Keep an eye on the pressure gauge while adding refrigerant, and stop when the low pressure reaches about 45-60 psi. Be careful not to overfill, as that can actually impair cooling. Feel the air vent temperature—if it's noticeably cooler, you've succeeded. Finally, make sure to close the valve tightly and disconnect the hoses quickly to prevent refrigerant leakage.

[McAlexa]

Adding refrigerant yourself is actually quite simple, but there are tricks to it. First, you need to figure out the refrigerant type your car uses—most vehicles nowadays use R134a. A basic refill hose kit costing around 30-40 RMB is sufficient. The key step is purging air: after connecting the new refrigerant can to the hose, slightly loosen the gauge nut to release some gas, then immediately tighten it when you hear a hissing sound—this removes air from the hose. Next, start the engine with AC on, locate the low-pressure port marked with an "L" in the engine bay. Hold the refrigerant can upside down, open the valve slightly and add slowly—adding too fast may cause frostbite. After about five minutes, check the air vents; if they feel icy cold and droplets form, it's time to stop.

[HopeMarie]

Before refilling, two things must be confirmed: Is there any leakage in the air conditioning system? Is there a shortage of refrigerant? If oil stains are observed at pipe connections, they must be addressed first. It's advisable to have a small electronic scale ready and refill according to the vehicle's specified refrigerant amount. I prefer to keep the car window open when refilling from the low-pressure pipe to hear the changes in the compressor's engagement sound. During refilling, ensure that both high and low-pressure gauges rise in sync, which indicates normal operation. If the low-pressure gauge needle suddenly starts shaking violently, stop immediately—it could be a sign of impending compressor failure. After refilling, don't rush to disconnect the pipes; let the air conditioning run for ten minutes to observe if the pressure stabilizes.