TSI Supercool Radiator Leak Detection Dye, Purple 8 oz — UV-Reactive Self-Measure Bottle

TSI Supercool RD8 is an 8-ounce purple UV-reactive coolant dye in a self-measuring bottle used to quickly reveal leaks in water-cooled radiators and engine cooling systems.

When you suspect a slow coolant leak, identifying the exact source fast saves time and prevents larger repairs. The RD8 formula mixes with radiator fluid and fluoresces under any UV light, making it simple to track down seepage, hairline cracks, or hose and gasket failures. The convenient self-measure bottle dispenses one-ounce increments so you add the correct amount without guesswork.

How do I use RD8 to find a radiator leak?

Add the dye to your cooling system while the engine is cool and run the vehicle briefly to circulate the product. Inspect visible components with a UV lamp—leaking areas will glow brightly. Follow safety guidance: let the radiator cool before opening and avoid skin or eye contact.

• Use 1 ounce per vehicle as a starting dose.
• Pour from the self-measure bottle to avoid overuse.
• Operate engine briefly to distribute dye, then scan with a UV light.
• Check hoses, clamps, radiator seams, water pump, and heater core area.

Will RD8 work with any UV light and coolant type?

Yes—the RD8 dye is formulated to fluoresce with standard UV/black lights commonly used in shops and by DIYers. It mixes with typical ethylene or propylene glycol-based coolants and water mixtures used in most water-cooled engines. Avoid mixing incompatible additives before testing to prevent masking results.

• Compatible with common glycol-based antifreezes.
• Detectable using handheld UV lamps or shop-grade black lights.
• Works in both closed-loop and open cooling systems.
• Do not combine with other leak dyes simultaneously.

How much dye should I use and how long until I can inspect?

The self-measure bottle makes dosing simple: use roughly 1 ounce per vehicle as directed for most passenger vehicles. After adding, run the engine for a short period to circulate the dye; small leaks often become visible immediately while slower leaks may require a few driving cycles to show. Clean affected areas with water and inspect under UV light for the clearest results.

• Typical starting dose: 1 ounce per vehicle.
• Short engine run usually sufficient; repeat after driving if needed.
• Wipe grime from suspect areas for better fluorescence visibility.
• Store remaining product in a cool, sealed place away from direct sunlight.

Does RD8 affect cooling system performance or require system flushing afterward?

RD8 is designed as a diagnostic dye and is compatible with cooling system fluids when used at recommended amounts. It does not permanently alter fluid performance when used for leak detection, but many technicians prefer to perform a routine coolant change if the system needs repair or contamination is suspected. Always follow manufacturer service intervals and disposal recommendations for coolant fluids.

• Formulated to be safe for short-term diagnostic use at recommended doses.
• Consider a coolant flush if repairs are made or if contamination occurred.
• Adhere to local disposal rules for used coolant and dye-contaminated fluids.
• Keep away from skin and eyes; use protective gloves and eyewear when handling.

Who is this for: RD8 is aimed at mechanics, service technicians, and hands-on vehicle owners who want a fast, visible way to locate coolant leaks without dismantling the entire cooling system. It’s useful for shop diagnostics, roadside troubleshooting, and routine maintenance checks where pinpointing a leak quickly reduces labor and repair costs. If you need a compact, easy-to-use UV-reactive coolant dye in a self-dosing bottle, the TSI Supercool RD8 is built for that task.