How to Refill Car Refrigerant?
4 Answers
Refilling refrigerant can be done from either the high-pressure side or the low-pressure side. High-pressure side refilling involves adding liquid refrigerant, which is suitable after leak detection and vacuuming. Note that the compressor must not be turned on during this method, the engine should be off, and the refrigerant can must be inverted. Here is additional information: Low-pressure side refrigerant refilling method: First, connect the manifold gauge set to the compressor and the refrigerant can. Open the refrigerant can, loosen the nut on the middle injection hose connected to the manifold gauge set until you hear the sound of refrigerant vapor flowing, then tighten the nut to expel air from the injection hose.
Last time I added refrigerant to my car by myself, and the steps must be clearly remembered. First, wear protective goggles and gloves, then locate the high and low-pressure pipe connections of the AC system—the high-pressure pipe is usually thinner. Make sure to buy the refrigerant model recommended by the manufacturer and never mix different types. Next, use a pressure gauge to check the system's existing pressure; if it's normal, no refill is needed. If the pressure is too low, invert the refrigerant can and screw it tightly onto the dedicated adapter. Start the engine and turn the AC to maximum airflow. Then, slowly open the valve while keeping an eye on the pressure gauge needle—make sure it doesn’t exceed the green zone. After filling, close the valve first before stopping the engine, and finally, use soapy water to check for leaks at the connections. The entire process must be done in a well-ventilated area since refrigerant gas is harmful to humans. DIY refilling may save money, but improper operation can damage the compressor. If you're unsure, it’s safer to let a professional handle it.
I'm the kind of person who enjoys studying cars, and adding refrigerant is actually quite particular. You must confirm there's a refrigerant leak before topping it up, as blindly adding it is just a waste of money. You'll need to prepare a pressure gauge set and adapter fittings, with the key being to locate the low-pressure charging port—usually the thick pipe in the engine bay. Start the vehicle with the AC set to maximum cooling and the fan at full blast. After connecting the can, don't rush to pour it all in at once; close the valve after each addition and shake the refrigerant can to fully release the gas. Pay special attention to monitoring the pressure changes—for household cars, maintaining the low-pressure side between 25-35 PSI is ideal. After topping up, take a couple of test drives; the AC vent temperature should be below 10°C to consider it a success. Some cars even have refrigerant recovery systems—environmental protection is important, after all.
Last week, I went to the 4S shop to recharge the refrigerant, and the technician taught me a few key points. The refrigerant can must be installed upside down to ensure liquid entry, and the O-ring must be confirmed intact before connecting the pipeline. The key is to control the filling amount—more is not better, as overfilling can damage the compressor. The technician explained while operating: first, vacuum for 15 minutes to remove moisture, as this step directly affects the cooling effect. During filling, the pressure gauge should not rise too quickly; a small 150-gram can should be added slowly in three or four steps. Special attention should be paid to filling in the shade during summer, as high temperatures may cause abnormal pressure. Finally, use an infrared thermometer to check the air vent temperature, which should be around 7 degrees Celsius to meet the standard. The whole process takes about 40 minutes, and professional equipment really makes it worry-free.
