ACDelco 4-in-1 Fluorescent Dye is a multipurpose fluorescent leak detection dye used in conjunction with ACDelco Ultra Violet (UV) Leak Detection Lamp Kit to pinpoint leaks in oil and oil-based fluid systems. The fluorescent dye can be used with gasoline and diesel engine oil, power steering fluid, and automatic transmission fluid. ACDelco 4-in-1 Fluorescent Dye can safely remain in the system after work is performed.