What are the reasons for undetectable minor leaks in car air conditioning?

[KevinLynn]

Car air conditioning minor leaks may be undetectable due to air conditioning compressor failure or expansion valve leakage. Below are the relevant explanations: 1. Air conditioning compressor: Compressor failure is an internal leakage, and this leakage location is difficult to identify during inspection. The end of the compressor might have insufficient sealing tightness. At the end of the stroke, when the refrigerant is compressed, an ultra-high pressure phenomenon may occur. At this time, if the end of the cylinder is not tightly sealed, or there are issues like pinholes, refrigerant may leak. This problem is quite troublesome and requires replacing the compressor. 2. Expansion valve leakage: Expansion valve leakage can cause changes in the refrigerant state, leading to issues. Attention should also be paid to the car's evaporator, as pinholes or cracks may also occur there.