What is the reason for car air conditioning refrigerant leakage that cannot be detected?
4 Answers
You can check places like the condenser. Below is the relevant introduction about car air conditioning: 1. Air conditioning layout: Different types of air conditioning systems have different layout methods. Currently, cars widely use integrated heating and cooling air conditioning systems. The layout form involves assembling the evaporator, heater radiator, centrifugal blower, and control mechanism together, referred to as the air conditioning unit assembly. 2. Air conditioning composition: Modern air conditioning systems consist of refrigeration systems, heating systems, ventilation and air purification devices, and control systems. Car air conditioning generally mainly includes a compressor, electronically controlled clutch, condenser, evaporator, expansion valve, receiver-drier, pipelines, condenser fan, vacuum solenoid valve, idle speed controller, and control system. Car air conditioning is divided into high-pressure pipelines and low-pressure pipelines. The high-pressure side includes the compressor output side, high-pressure pipelines, condenser, receiver-drier, and liquid pipelines; the low-pressure side includes the evaporator, accumulator, return pipelines, compressor input side, and compressor oil sump.
I've been driving for over 20 years and have encountered situations where the AC refrigerant leak couldn't be detected, which is quite common. The main reasons are that the leak point is too small or in a hidden location, especially cracks in places like the evaporator core or compressor interface that are invisible to the naked eye. Sometimes the leak is intermittent, not occurring during detection; or the system pressure is too low, and the tools aren't sensitive enough to catch the issue. I recommend first applying soapy water to suspicious areas to observe for bubbles. If that doesn't work, add fluorescent dye, run the system for a few days, then use a UV light to locate the leak. Regular maintenance should include checking for aging seals and replacing them promptly—don't wait until the AC completely fails to realize the trouble. If you really can't find it, don't force it—take it to a professional shop to use an electronic detector.
I enjoy working on my car in my spare time, but it's frustrating when the AC is leaking refrigerant and I can't locate the source. Common issues include dried or poorly compressed O-rings causing micro leaks, or hard-to-spot locations like deep corners of the condenser. Another pitfall is that fluorescent dye takes time to penetrate – rushing the inspection might cause you to miss the leak. I've tried using a dedicated UV light for scanning, which can reveal some clues. Don't just focus on the high-pressure lines; the expansion valve connections might also have hidden leaks. Remember to regularly maintain and replace filters to prevent seal failures. When doing DIY repairs, wear gloves to protect yourself – Freon is toxic. If you really can't find the leak, invest in a good quality leak detector – it's a small expense that can save you big headaches.
I've seen cases where air conditioning refrigerant leaks couldn't be traced, mainly because the leak points were too tiny or hidden in deep, hard-to-access areas. For example, pinhole cracks in evaporator coil pipes that regular probes can't reach, or system pressure being too low to detect flow leakage traces. Intermittent leaks only occur under specific temperature and pressure conditions, making them hard to spot during testing if nothing happens. Improper installation with loose connections is also common, but easily overlooked during visual inspections. It's recommended to conduct a comprehensive disassembly or pressure testing to confirm the issue. Safety first—don't attempt disassembly blindly. Professional shops with experience and proper equipment are more reliable for finding the source.
