TSI Supercool Synthetic U/V Leak Detection Dye, 1 oz, 1 Application

This stuff was AWESOME ! I didn't even have to use a UV light. My leak was clearly visible in the direct sunlight. I'm very impressed with this product.

Awesome stuff. I never would've found the leak without this. It was in a fitting if a very durable feeling hose. The color provided a nice day to see glow under black light. Easy to use, just put it in. I didn't have any long term staining either.

Was skeptical at first but used it and it makes it so much easier to find a leak and most of the time you dont even need the flashlight to spot it. Color is nice and bright to see definitely worth the money id buy again. Worked great for us even though the radiator is shot.

Excellent method for leak identification. I emptied all of the contents of the bottle into the coolant reservoir of my 2016 F-150 5.0 (12.5 quarts coolant system), and let it circulate through the system through 2 days of driving to and from work (about 60 miles total). After the second day, I popped the hood and shined my UV light into the engine bay and immediately found where my leak was happening at. The bottom side of the water pump, down to the timing chain cover and cross-member all lit up like a cartoon depiction of radioactive waste. This stuff worked amazingly well to help my find my coolant leak. It'll be at the top of my list of coolant leak diagnostic methods in the future.

Glows very bright

I think if you work on your own stuff you should definitely have a bottle on hand just in case. I had been fighting coolant loss in an 05 Pontiac Montana van and after replacing the radiator cap and the water pump which both leaked I was still losing coolant. Put this in ran it for a couple days till my next free day and found 3 more leaks. One in the corner of the radiator where you couldn't see it and two in a steel line. They would seep slightly but I guess the engine heat would dry them off before I ever noticed them. Definitely noticed the green residue after using this tho. I bought a cheaper Uv flashlight on here and it did me just fine. Highly recommend if you're chasing leaks like I was.

Dumped into my radiator to find a small leak in my Jeep. I could smell the burning fluid, but could not find a leak and didn't have any drips in my driveway. I gave this product two days of driving around and then I grabbed a UV light and almost instantly found the leak. A small leak near the thermostat was dropping coolant on the belt and slinging it all over the front of the motor. I was able to fix the leak quickly and rinse the extra coolant and dye off the motor. I checked again the next evening and no new leaks. Great product that saved me weeks of looking for a leak.

Worked well and easy to use diagnosing and tracking down a leaky water pump. Only hiccup is that my bottle arrived with no lid so I ended up wasting most of the bottle. More than a little frustrating given the cost

Sooooo very concentrated and BRIGHT. This product helped me diagnose a gremlin in my coolant system. 5/5 stars, great product.

The only Radiator specific dye that i could find. All others are for oil and are not compatible with coolant. It works amazing and it glows really bright fluorescent yellow under 365nm uv light form a cheap torch. The ammpount was more than enough for a very large LR4 V8 with dual AC system.

Works really well, even without a black light you can clearly see the leaks, recommend.

Great stuff

Worked very well. Makes it very easy to track where coolant is leaking to with a UV light. Lights up very bright when UV Light is shown on it