How to Tell If Car AC Refrigerant is Low?
2 Answers
In the refrigeration system, insufficient refrigerant will cause the evaporator to "stop vaporization", and the compressor intake pressure will consequently drop. Even if the refrigeration system is still running, the air temperature inside the vehicle will rise. The refrigerant level can be checked through the sight glass, generally by two methods: 1. Visual and tactile empirical judgment - If the refrigerant liquid appears cloudy or foamy in the sight glass, it indicates insufficient refrigerant and possible leakage; simultaneously, there should be no significant temperature difference between the high and low pressure pipes when touched by hand (normally the high pressure pipe is hot while the low pressure pipe is cool). 2. Pressure judgment method: Various conditions of the refrigeration system can be determined from the high and low pressure gauges of the compressor. The pressure judgment procedure is as follows: (1) Run the engine at a higher idle speed (about 1000r/min), and set the cabin air temperature to around 21°C. At this time, the high pressure reading should be 1034kpa. If the ambient temperature is lower and the high pressure is below this value, partially block the condenser coils with newspaper or cardboard to increase the pressure. (2) If the ambient temperature is too low, stop the fan and use a heater to warm the cabin air. (3) When the ambient temperature is above 27°C, the high pressure will exceed 1034kpa. (4) Under the above conditions, the sight glass should be clean, transparent, and free of visible bubbles, otherwise it indicates insufficient refrigerant in the system.
To determine if the car's air conditioning refrigerant is insufficient, I've summarized it from my driving experience. After starting the car, if the air from the AC doesn't feel cold enough or the temperature drops too slowly, these are clear signs. Additionally, there's a small glass window on the AC pipeline in the engine compartment called the sight glass. If you see it cloudy or bubbles moving inside, it usually indicates low refrigerant. However, this is just a preliminary check. It's best to visit a professional repair shop to have them measure the high and low pressures with a gauge. Low readings indicate a problem. Refrigerant shortages are often due to aging pipelines leaking or natural depletion. I recommend not adding refrigerant yourself, as it can easily damage the system or cause leaks, making repairs more expensive. In summer, a weak AC not only causes discomfort but can also affect driving concentration, so it's best to visit a shop at the first sign of trouble. Regular AC maintenance can save a lot of hassle.
