LF3001 Automotive Engine Coolant Leak Detection Dye, Services Radiators, Hoses, Heater Cores, Water Pumps, (6) 1oz Ultraviolet Fluorescent Dye Bottles, Made in USA

Allowed me to pinpoint a coolant leak that had plagued me for months. A hot EGR valve had burned through a firewall heater hose. The hot valve vaporized the coolant. That’s why there was never any obvious coolant on the engine or on the driveway . The dye showed me exactly where that elusive leak was. I replaced the heater hose and problem solved. I would have never found that darn leak without this product. Used a UV light to light up the dye. The leak stood out like a beacon. A Plus rating on this product.

It does what it says. I was able to confirm my coolant leak is not external and continue investigating.I suggest using something to siphon some of the coolant out of the radiator to make room for the product.

This helped me confirm it was my water pump that was leaking.

Pour the entire 1 0z in a cold engine......run the vehicle till operating temperature.......use a special light ( not included ) to find the antifreeze mixed with the solution. Very easy to use.

This item is great to help finding leaks. Just pour it in reservoir, run the vehicle a while and then when its dark enough you can use a UV light and find the leak. The only thing that can make this better is if could fill the leak, but that's probably asking too much.

Worked kinda, hard to see even with blue light but solution was clumpy and a lot of sediment on bottom. Maybe it was too cold out for it to dissolve and pour but could be old as well not sure. Didn’t really help me find a leak but replaced radiator and hoses anyway so all good.

As a self-proclaimed "YouTube mechanic", I am able to do a lot of automotive repairs myself. Diagnosing problems is frequently the biggest hurdle. I knew that I was losing coolant, but after checking all the fittings on the cooling system and frequent checks in the engine compartment for leaks, this coolant leak was eluding me. I finally decided to buy this leak detection dye and a small blacklight to pinpoint the source of the leak.I cracked the small bottle open and checked it with my blacklight. It did NOT fluoresce, so I was a bit skeptical that it was going to help me find my leak. But, I'd come this far, so I decided to pour it into my coolant reservoir. As I did, a couple drops dripped onto the edge of the wet reservoir opening and POW, bright green. So, it reacts to the water in the coolant and is very easy to see (even without the blacklight).After running the engine for a few minutes to let the coolant circulate, I found that the fitting near my heater core was dripping a drop of bright green coolant every couple seconds. The source of the leak was identified, and angels sang.Days/Weeks of guesswork solved very quickly by this product. Would absolutely add this to my cooling system diagnostic kit.

I got this for my husband that has been having antifreeze leak. He was able to spot it and fix it. Update: months later, had another leak and was still able to find it!