When you find a system that is low on refrigerant having a good leak detection strategy will be crucial in saving you shop time. Ultra Violet (UV) Dyes can be a very reliable method of leak detection. When adding dye to a system that leaks, just let the system circulate the dye. All additives and dyes suspend in the oil and circulate as part of the oil. So, when there is a leak in the system, the oil and dye will leak also. Shine your UV light onto the system and the dye should fluoresce. Wherever you see fluoresces then that is where the leak will be. But don't stop when you find the first leak because there may be more leaks to discover. Dyes have become a very acceptable method of leak detection. In the past some have considered dyes to be a contaminant to the a/c system. Now, most of the original vehicle manufacturers add UV dyes to the a/c system on the assembly line.
