How to Determine if a Car's Air Conditioning is Low on Refrigerant?
4 Answers
Methods to determine if a car's air conditioning is low on refrigerant: 1. During normal continuous operation of the air conditioning, if there are continuous bubbles in the sight glass, it indicates a lack of refrigerant; 2. Open the car hood and check for oil stains at the air conditioning system joints—if present, it indicates a lack of refrigerant; 3. During normal continuous operation of the air conditioning, if there are no bubbles in the sight glass, but brief bubbles appear when the air conditioning stops, it indicates the refrigerant level is normal. The process of refilling air conditioning refrigerant is: 1. Evacuate the system, close the manual valves on the pressure gauge and the high and low pressure manual valves; 2. Connect one end of the hose to the injection valve fitting of the refrigerant can; 3. Open the refrigerant can, loosen the nut on the pressure gauge hose to allow some gas to escape, then close it; 4. Open the high-pressure side manual valve and invert the can; 5. Inject the specified amount of liquid refrigerant, then close the refrigerant injection valve and the high-pressure manual valve.
I notice that the most obvious sign of poor air conditioning performance in summer is the reduced cooling effect, where the cabin temperature doesn't drop even after running for half an hour, leaving it stuffy. I conduct some simple tests: feel the air vents while driving—if the airflow is normal but there's no cool air, it might indicate insufficient refrigerant; listen for abnormal clicking sounds or frequent cycling of the compressor, which suggests it's under heavy load; also check if the AC light is flashing. This becomes particularly noticeable in hot weather, affecting driving comfort and even safety, such as increasing the risk of heatstroke during long trips. Regular checks are crucial to prevent worsening into system damage or increased fuel consumption. Getting a professional inspection at a shop early is the most reliable solution.
As someone who frequently tinkers with cars, I use an AC pressure gauge connected to the high and low-pressure ports for diagnostics. Normal low pressure should be around 25-45 PSI, while high pressure ranges between 150-250 PSI. Readings significantly lower or fluctuating wildly indicate refrigerant loss. Oil stains or greenish residue around pipe joints are telltale signs of leakage, and a warm low-pressure pipe (which should feel icy) further confirms it. This issue not only compromises cooling efficiency but also forces the compressor to overwork, potentially causing severe long-term damage and increased energy consumption. DIY refrigerant top-ups require caution due to imprecise measurements and environmental concerns. I'd recommend consulting a professional technician for a comprehensive system scan to ensure safe repairs.
Air conditioning not cooling is dangerous in hot weather. I will immediately pull over and turn on hazard lights to prevent heatstroke. To determine a lack of refrigerant, observe if the cabin temperature rises quickly, air vents are not cold, or the system warning light is on. No frost on the low-pressure pipe or abnormal temperature difference indicates poor circulation, possibly due to a leak. Leaking refrigerant not only affects driving but also harms the environment. Timely inspection and repair can avoid the risk of breakdown on the road. Safety first—don't delay. Make it a habit to have a professional check before the transition from spring to summer.
