ACDelco Coolant System Fluorescent Tracer Dye is a fluorescent leak detection dye for traditional coolant systems. This fluorescent tracer dye quickly pinpoints the exact location of coolant fluid leaks. It is a safe and easy method that helps eliminate guess work, save labor, and speed up service. ACDelco Coolant System Fluorescent Tracer Dye may also be used to isolate power steering system leaks. ACDelco Coolant System Fluorescent Tracer Dye can be used with DEX-COOL coolants, but it may change the color of the coolants.