FJC Products Universal Radiator Coolant Dye MIX: 1 ounce of dye to 4 gallons of coolant. Compatible with all radiator coolants. Will NOT change the color of the system coolant. Part# 4926 1 ounce bottle Universal Radiator Coolant Leak Detection UV dye. Will not change the color of any coolant. Can be detected using any UV or blue light