ACDelco GM Original Equipment 10-5045 Multi-Purpose Fluorescent Leak Detection Dye - 1 oz

Must have in each technicians or enthusiast toolbox! Had oil seepage in hard to reach areas. Washed engine really well, confirmed with UV light nothing is glowing. Poured dye in and gave car quick drive around the block. Allowed engine bay to cool a bit and inspected with UV light: instantly found larger oil leak through dipstick tube and tiny seepage at timing cover. Saved hours on troubleshooting. Extra benefit, since dye can stay in the system, was able to confirm repairs worked. In my case dye still glows after driving for 200km

I put the whole bottle in my 7.3. This truck takes 4 gallons of oil for anyone wondering how much you need, well, it dyed enough for me. I shined in the bottle to see the color, it's bright orange almost. I've already found one leak, and maybe that's it. But I'll have to run it longer to know for sure. Good stuff, worked as intended.

Works as it should.

I have been fighting transmissions leaks in my 67 Camaro for ages. The dye really lets you see the source of the leak. I cleaned under the car really well and added the dye. Then I drove it a few miles. Using the special glasses and the black light I got with the dye, I could see exactly where the fluid was leaking from. The dye will not hurt anything.

So I have a leak on my recently built hot rod that only has 300km. I figured I would get a baseline and go over the engine with the UV light ahead of time just out of curiosity. I've only ever used castol GTX for oil for the break in. Turns out my current leaks lit up like crazy with the UV light before even using the addative. I also found that Lucas synthetic gear oil lights up like crazy as well. I tested out the addatuve and it definitely does work. Turns out it lights up just the same as the Castrol tho so was tough to pinpoint the leak.