I picked up a bottle of this dye at NAPA to help find an ever-growing coolant leak and thought I’d share the results.
Within 10 minutes of idling with it in the radiator, the dye was visible in two places. One was at the upper radiator hose, and the other was at the heater hose fittings:
This is just during the day – the dye is highly visible in the dark if under a blacklight. It was hard to get good pictures with just the blacklight, but here are the ones I took:
Needless to say, I’ve decided the bottle of dye was worth every penny. It helped me locate three coolant leaks (two of which almost instantly) and saved the trouble of replacing the part I thought was leaking. The leaks ended up being the upper radiator hose, heater hose fittings, and a pinhole leak in the radiator.