What are the methods for checking refrigerant leaks?

[Gandalf]

Methods for checking refrigerant leaks include: 1. Visual inspection method; 2. Soap bubble method; 3. Nitrogen water leak detection method; 4. Halogen leak detector method; 5. Gas differential pressure leak detection method. The steps for refrigerant charging are: 1. Prepare refrigerant that matches the required model; 2. Prepare qualified refrigerant charging tools; 3. Connect the car air conditioning system to the charging tool adapter; 4. Evacuate the system; 5. Charge the refrigerant. The properties required for refrigerants are: 1. Excellent thermodynamic characteristics to ensure high cycle efficiency within the specified temperature range; 2. High heat transfer coefficient, low viscosity, and low density; 3. Good miscibility with lubricating oil; 4. Safety requirements include being non-toxic, non-irritating, non-flammable, and non-explosive; 5. Good electrical insulation properties.

[QuinnRose]

Oh no, last time I found my car's AC wasn't cooling properly, and it turned out the refrigerant was leaking! Here's a handy folk remedy: prepare some thick soapy water and a small brush, then focus on spraying the AC pipe joints, condenser edges, and compressor sealing rings – bubbles will puff up like blowing balloons. Metal joints are the most prone to leaks, especially in older cars that have endured lots of bumps, as rubber seals can develop hairline cracks when aged. If you check at night with a UV light, some refrigerants contain fluorescent agents that glow, making leaks easier to spot than in daylight. Remember to wear gloves and goggles—refrigerant can cause frostbite on contact! Small leaks might be manageable DIY, but if the whole condenser is leaking like a sieve, you’d better call a professional.

[LaLyla]

Having repaired cars for over a decade, I can pinpoint 70% of refrigerant leaks with my eyes closed. The key is using the right tools—an electronic leak detector is the most accurate. Slowly sweep the probe along the high and low-pressure lines; the faster the beeping, the closer you are to the leak. Feeling for oil stains works too, but the mixture of compressor oil and dust can be sticky like asphalt. Pay special attention to three areas: the compressor shaft seal, condenser fins, and expansion valve connections—especially if the undercarriage has been hit, as deformed aluminum tubing can cause hidden leaks. The latest method is even more advanced: after vacuuming the system, fill it with helium and use a mass spectrometer to detect leak rates, catching even micro-leaks as small as 0.1 grams per year. But for average car owners, it's not worth the hassle—this equipment costs tens of thousands.

[VonDonovan]

When the air conditioning suddenly fails just after starting the car, it's most likely due to refrigerant leakage. The quickest way to check is by feeling the temperature difference between the high and low-pressure pipes: normally, the low-pressure pipe should feel cool and may even frost over; if it's at room temperature, there's probably a leak. You should also check the pressure gauge—if the low-pressure side drops below 20psi after turning on the AC, there's definitely a serious leak. Here's a money-saving tip: buy a bottle of fluorescent dye from Taobao for just over ten yuan, inject it into the system, and use a UV flashlight at night to spot leaks—they'll glow like fireflies. However, refrigerant is corrosive, and DIY refilling carries risks. A repair shop can replace the seals and recharge the refrigerant for around 300 yuan, including labor.