A/C Pro Certified Auto Pro Oil and Fuel System UV Dye Leak Detection for Cars & Trucks & More, 1 Oz, 374CS, Universal

With this oil I was able to trace the mystery leak in my transmission. Worked as advertised. Worth the money. I used an UV flashlight I purchased separately.

I used this dye to help diagnose a fuel leak in a carburetor. It worked outstandingly well. With just a drop of it in a few ounces of fuel, it lit up bright when exposed to a little UV light. I would not have otherwise been able to find the leak since it was a small weeping leak that did not appear “wet” but the dye showed exactly where it was.

Worked as it should. Great help for locating the leaky spot.

For better success than me: 1) Highly suggest cleaning oils and sludge off engine before using. 2) Don't pour dye straight into engine. - Mix it into fresh oil and pour into engine. Ideally drain all oil and pour in fresh oil with dye into engine/ 3) Don't drive after pouring in dye. My mistakes: 1) very very very dirty engine due to persistent leak for 7 years. Very hard to find the leak. Not sure I even found it exactly yet. 2) pouring dye into 500mL fresh oil and pouring into 3-4quarts of 5000 mile old oil in the engine already. - the oil was so dirty that the dye ended up looking like a light snot green color instead of vibrant yellow. - better to drain old oil and mix in dye into fresh oil and fill engine. 3) don't drive after putting dye in else you will have dye all over the place, which isn't helpful when it already hard to see the dye due to 1 and 2 above.

Worked great!

I use these on customers cars and it always pin points the leaks

Did the job! We found the leak ourselves and it gave us a sense of security when we went to the mechanic so they didn’t try and funny business

It's ok. It does work, but I wish it was brighter, kind of hard to see.

Works great pinpointed oil leak! Have had a slow oil leak on our 2002 Grand Am for the past 4 years. Nothing serious just an annoying constant oil leak In our driveway. Was leaking about 1 quart between each oil change. At first was convinced it was the pan so changed the oil pan gasket. This did not solve the leak nor did a stop leak product. So purchased this DYE put it in and went for about a 50KM drive. Brought it home, jacked it up and had a look in the dark using a black-light flashlight. Lots of oil around the pan is why I originally thought that was the leak source. Using the black light, the DYE outlined that the leak was coming from a much higher spot and flowng down on to the pan giving the illusion that the oil pan was at fault when in fact it was not. Got my answer and found the leak source

Used it for thr first time yesterday and discovered the source of my oil leak quickly . You will need a black light but they are cheap. Recommended .

Does not identify leak

It really helped to detect the engine leak

Used this to track down an annoying oil leak. Worked almost instantly. Very impressed. Wish it was available locally in a larger size.