ACDelco 10-5046 Dex-Cool Leak Detection Tracer Dye - 1 oz Designed to quickly pinpoint leaks in cooling systems that use DEX-COOL (orange) coolants Special formula will not change the color of the coolant Fluorescent dye assists with visual leak detection to eliminate guess work Works in conjunction with the ACDelco Ultra Violet (UV) Leak Detection Lamp Kit (PN 12377979)