Mastercool 53610 Oil / ATF / Gas Fluorescent Dye (1 oz Bottle) This multipurpose dye works in the automatic transmission, engine oil and in fuel tank leak detection. For Engine Oil (gas and diesel): 1 oz is 1 vehicle application per 4-5 quarts of oil. For Fuel Tanks (Gasoline and Diesel): 1 oz is 1 vehicle application per 2 gallons of fuel. For Automatic Transmissions: 1 oz is 1 vehicle application per 4-5 quarts of ATF fluid.