ACDelcoGM Original Equipment 10-5057 (12378563) Engine Cooling System Tracer Dye - 1 oz

I have a pc water cooled setup that leaks pretty badly yet not bad enough to see any water. I used about 2 tablespoons of this dye with a cheap UV light and glasses combo. I was able to instantly find the leak. Just to make sure it was leaking, I shaped a napkin to a point and put it where I saw the leak. As a side note, a phone camera sees UV light great as seen in the pictures, so the glasses aren't really needed but that's up to you. This was a 1977 Pontiac Bonneville without A/C heater core that I used as a custom radiator for various computers for over 15 years now. Now to finally retire the thing. Back then this full copper heater core only costed $35 and PC water cooling components were rare and very expensive.

I've had a coolant smell coming from the front of my Jeep since I bought it 3 years ago and I couldn't find the leak to save my life. I've only added a quart of coolant the entire time, so I knew it wasn't that bad and I watch the level like a hawk. I decided to try this stuff just for fun and wow! I found it in daylight as soon as the engine warmed up without a uv light! It was the last place I would have guessed because the seal on the radiator cap looked fine. Once the system pressurized, it pushed past the seal and turned into steam. So THAT'S why I never saw any leaks! I was ready to replace the radiator, but all it needed was a $10 radiator cap! BUT WHATEVER YOU DO, DON'T SPILL IT! This stuff is SUPER concentrated! I spilled the smallest amount while pouring it in and tried to wash it off with the hose. Now my driveway looks like a nuclear waste spill. This is all from spilling about 1/4 ounce. And no, it's not coolant on the ground. Highly recommended!

The media could not be loaded. Amazing stuff. Seriously concentrated. Poured full 1 oz. bottle into my 70 gallon test tank, to run through outdrive, sea water pump and then 4.3 liter engine, Volvo Penta inboard/outboard fishing boat. With the aid of a UV diagnostic flashlight was able to confirm an intermittent leak on the Engine water pump.Great stuff.

Had a coolant leak I couldn't find at all. Put this in the coolant reservoir and drove the truck for a couple hours and found the leak glowing coming from under the water pump. Good stuff

Immediately found the leak in my system. Only thing I dislike is the instructions say to use the whole bottle. This stuff is potent. Only use the whole bottle if your doing a 5 liter engine. You should use a quarter or half on a small compact car. Weirdly, it goes in red and is meant for dexcool. But after it's mixed in the whole system turns iridescent green.

THIS STUFF literally GLOWS in the DARK-if you have a LEAK you will find it- even in the engine oil.

I was losing a small amount (3 or 4 ounces per week) of antifreeze from my 2004 Toyota Camry after servicing the cooling system and replacing the radiator hoses. I could not see a leak, so I replaced the radiator cap, added stop leak and hoped that it wasn't a head gasket. I was thinking of adding a bottle of stuff to seal the head gasket when I ran across this product. I purchased this product along with a black light flashlight for about $15.00 and added half the bottle to the radiator. It then became apparent in short order that I had not tightened the lower end of the lower radiator hose sufficiently. The dye showed that antifreeze was leaking onto the splash guard and evaporating before it leaked on the ground. The dye easily rinses off with a hose so any new leaks will be readily apparent. If I were doing it again, I would start with the dye but only use about 1/4 of the bottle.

You'll easily be able to find the leak with this.