TSI Supercool RD8 Radiator Coolant Water Based U/V Leak Detection Dye (Self Measure Bottle), Purple, 8-Ounce Bottle

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.

This works absolutely perfect, I put the whole bottle and probably shouldn't have because my coolant was super neon green but I sure did find my leak with this I definitely recommend

I mean it works. Can't ask for anything more. Used it to find a coolant leak after replacing radiator and hoses. I was still leaking coolant after getting it replaced at a shop and I decided to take it into my own hands to figure out where the leak is coming from. Turns out they didn't tighten the hoses!! Probably saved me from them scamming me out of more money.

Works well, but I'd use way less than is recommended. This stuff is crazy concentrated and messy.Only downside is once it's in there, it's a bear to get out. It'd take a ton of flushing to get it all out.

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

Works wonder for any automotive fluid leak, Cheaper than NAPA. Glows like its radioactive :)

Sadly, it revealed more leaks than expected! Excellent for finding leaks.

I’ve been chasing this micro leak for over a month. It’s been very difficult to find because it wouldn’t really show signs until after about 20 miles of driving. But it would release the pressure from the overflow cap and spray coolant everywhere and I couldn’t pin point the leak. I FOUND IT IN 3 MINUTES USING THIS PRODUCT. I HAD A BLACK LIGHT WHICH WAS USED IN THE 1st PICTURE. 2nd photo is without the black light. It’s actually visible without it but I suggest grabbing one off Amazon. Love the results.