From oil leaks in hydraulic and engine oil to water leaks in coolant and water/glycol systems. Add the dye to the fluid, shine a UV lamp, and the leak point fluoresces so you can pinpoint it — a lineup of 3 for oil leak detection and 1 for water leak detection, 4 SKUs matched to the carrier fluid and application.
UV fluorescent dye is an oil and water leak detection additive that is mixed into a carrier fluid (hydraulic oil, cooling water, etc.) and then illuminated with an ultraviolet (UV) lamp so that any leak points fluoresce brightly and can be located precisely. It is an established method adopted by hydraulic OEMs, automakers, and HVAC specialists. Inject a small dose of dye into the carrier fluid (0.05–0.20% for oil depending on the oil type; 0.01–0.05% for water-based fluids) and operate the equipment for half a day to a full day; any fluid escaping from a leak will glow under UV light, revealing pinholes and seepage-level leaks that are invisible to the naked eye.
Leak detection dyes for oil-based carrier fluids — hydraulic oil, engine oil, refrigeration lubricant, and more. Select by emission color and volume.
Oil Finder Yellow
Volume: 1000ml
Oil Finder Yellow (case pack)
Volume: 1000ml × 12 bottles
Oil Finder Yellow
Volume: 30ml × 5 bottles
For other oil leak detection dyes, please contact us separately. We will advise on emission color, volume, and other requirements.
Contact UsLeak detection dyes for water-based carrier fluids — coolant, water glycol, and process water. Select by emission color.
WATER FINDER BLUE 1L
Water fluorescent dye (blue)
For other water leak detection dyes, please contact us separately. We will advise on emission color, volume, and other requirements.
Contact UsA UV-A lamp with a 365nm center wavelength that makes the dye glow so you can spot leaks.
High-intensity UV lamp (11.2V dedicated battery)
UV intensity 30,000 μW/cm² / 22cm beam
A spray cleaner that removes leftover dye after inspection — just spray and wipe.
UV Dye Cleaner
Volume: 60ml
For other UV lights and cleaners, please contact us. We will advise on UV intensity, power supply, volume and other site requirements.
Contact UsProven with many construction machinery manufacturers and automakers in Japan. Inspect in three steps without stopping your equipment.
Enter the volume of oil or water (L) you use to calculate the number of products required.
| Fluid | Volume (enter) | Dosage | Dye required |
|---|---|---|---|
| Light hydraulic oil | 0.05% | —ml | |
| Dark hydraulic oil | 0.10% | —ml | |
| Engine oil | 0.13% | —ml | |
| Compressor oil | 0.20% | —ml | |
| Fuel (gasoline / diesel) | 0.08% | —ml |
Enter the volume of oil (L) to see the amount of dye required, based on the dosage rate.
Enter a volume to see the total amount of dye required and the recommended pack size.
| Model | Contents | Oil volume per bottle (guide) | Best for |
|---|---|---|---|
| LL-OFY-P5 | 30ml x 5 | approx. 60L (light hydraulic oil) | Small equipment, spot checks |
| LL-OFY-Q | 1000ml | approx. 2,000L (light hydraulic oil) | Medium to large equipment |
| LL-OFY-Q/M12 | 1000ml x 12 | approx. 2,000L per bottle (same) | Multiple machines, regular inspections |
Add the dye directly to the tank at a standard 0.05% of the hydraulic oil.
Run the equipment for about half a day to a full day so the oil and dye circulate thoroughly.
Shine a UV lamp on suspected areas and any leak point will fluoresce. See UV lights for fluorescent dye
| Fluid | Volume (enter) | Dosage | Dye required |
|---|---|---|---|
| Water | 0.01% | —ml | |
| Water glycol | 0.05% | —ml | |
| Other water-soluble fluids | 0.05% | —ml |
Enter the volume of fluid (L) to see the amount of dye required, based on the dosage rate. If the fluorescence is weak, increase the dosage up to a maximum of 0.2%.
Enter a volume to see the total amount of dye required and the recommended pack size.
Add the dye directly to the tank at a standard 0.01% of the water or water glycol.
Run the equipment for about half a day to a full day so the water and dye circulate thoroughly.
Shine a UV lamp on suspected areas and any leak point will fluoresce. See UV lights for fluorescent dye
Real-world examples of UV fluorescent dye in the field, from maintenance leak checks to pre-shipment inspections. Even on piping caked with grime and iron powder, or on seepage too faint to judge by eye, circulating the dye and shining a UV lamp pinpoints the leak.
An aging machine in service for over 30 years was losing a full drum of hydraulic oil every four days. Iron powder on the piping left the leak point unidentified, but with the dye circulated at 0.05% beforehand, a UV lamp pinpointed the leak even on heavily fouled components.
The source of a hydraulic oil leak on a snow-removal wheel loader was unknown, and oil leaks on snowy roads are a particular hazard. With the dye, the leak at the control valve elbow was found easily.
It was difficult to tell an actual leak from externally deposited fluid, and inconclusive visual checks meant an overhaul — driving up inspection man-hours. A genuine leak at the engine mating surface can now be told apart from residue, making the dye ideal for pre-shipment inspection.
It supports oil-based fluids such as hydraulic oil, engine oil, spindle oil, gasoline, diesel, and jet fuel, as well as water-based fluids such as coolant and water-glycol. Choose the oil-type or water-type fluorescent dye according to your application.
Yes. UV fluorescent dye inspection is non-destructive and requires no shutdown. Simply add the fluorescent dye, operate the equipment for half a day to a full day, and then illuminate with a UV lamp. Leak locations can be identified in real-time while the equipment is operating.
Please feel free to contact us for product details, quotes, and more.