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

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.

Works well and easy to see with a black light.

Very concentrated as others have said. Don't use more than half to start with! Super great dye!!! I highly recommend!! It makes it easy to find the leaks!!!

I'm getting old, don't wanna waste more time then needed looking for leaks. This dye works awesome, although 1oz per system seems to be abit much imo. Think you can get away with .5oz no problem. Good and bright under the uv, pin pointed my leak easily.

Helped me find find my leak on my 2015 Chevy Sonic, one cap was enough for me to find the leak.

This stuff is very concentrated. Just a small amount is enough to dye an entire cooling system. It helped me find a small leak that would have been very difficult to see otherwise. Super easy to use - just dump it in and let it cycle. Be careful not to spill or splash though.

Everything arrived as advertised. I haven't used it yet but looks to be perfect! I will post pictures after I use it.

Nice and bright fluid really helped me find my leaks. It really helped me pinpoint my coolant leak, sadly that leak was from the intake manifold instead of something easy.