What is the method for adding refrigerant to a car air conditioner?
2 Answers
There are two methods for adding refrigerant to a car air conditioner. One is high-pressure side charging, which is suitable for charging after leak detection and vacuuming. Note that the compressor must not be turned on during this method, the engine must be off, and the refrigerant tank must be inverted. The other method is low-pressure side charging, where gas is added. This method is characterized by slow charging speed and is typically used for replenishing refrigerant. Situations when a car air conditioner needs refrigerant: 1. When the air conditioner is operating normally, continuous bubbles in the sight glass indicate insufficient refrigerant, which needs to be added; 2. When the air conditioner is operating normally, no bubbles in the sight glass, and no temporary bubbles appear when the air conditioner is turned off, it means there is too much refrigerant, which needs to be released; 3. When the air conditioner is operating normally, no bubbles in the sight glass, but temporary bubbles appear when turned off, it indicates the refrigerant level is normal; 4. If the sight glass cannot be found, open the car hood and check if there are oil stains on the air conditioning system joints. If there are, it likely indicates a lack of refrigerant.
I often recharge my car's AC refrigerant myself to save some money. The preparation is simple: get a refrigerant recharge kit that includes a pressure gauge and refrigerant can, locate the low-pressure port in the engine bay (usually the one with a blue or black cap), and clean it. Wear gloves and goggles, start the engine with the AC set to the coldest and highest fan speed, then connect the tools to vacuum for a few minutes to remove air – this step is crucial, don't skip it. Slowly add refrigerant like R134a while keeping an eye on the pressure gauge to stay within the middle green zone; overpressure may damage the compressor. After refilling, spray soapy water on the connections to check for leaks – no bubbles mean it's safe. The AC cooling effect improves immediately after recharging, but remember: if your car is old and needs frequent recharges, there might be a leak in the system. It's best to check the pipes or condenser, otherwise it's just a temporary fix. DIY is rewarding, but beginners should watch more tutorial videos – safety first.
