A/C: UV Refrigerant Leak Detection
Hard-to-find leaks can often be detected with a UV leak detection kit. They contain dye, a UV light, and a pair of yellow glasses that increase the intensity of the leaking dye.
The dye used in these kits is not interchangeable between refrigerants. Red dye is used to detect leaks in R-12 systems. This dye cannot be used in R-134a refrigerant systems and must be completely flushed out during a retrofit. Some dyes are used to detect leaks in the coolant system as well.
Use a halogen/refrigerant leak detection sensor or UV leak detection light at the drip tube and vents to seek any refrigerant leaking from the evaporator core. This procedure will help verify a leaking evaporator core.