Leak Check Test With Black Light

Oil-soluble aniline or fluorescent dyes premixed at the rate of 2.5 ml (1/2 teaspoon) of dye powder to 0.23 liter (1/2 pint) of transmission fluid have proven helpful in locating the source of fluid leakage. Such dyes can be used to determine whether an engine oil or transmission fluid leak is present, or if the fluid in the transmission fluid cooler leaks into the engine coolant system. A black light must be used with the fluorescent dye solution.