 From the labs at Lucas Oil Products, Lucas Oil Complete Engine Treatment is a multifunctional cleaner plus lubricant. For every fill-up of gas or diesel, add one 16-ounce can of Lucas Oil Complete Engine Treatment. One bottle can treat a tank of up to 21 gallons. Its special additives allows a better fuel burn to help increase your miles per gallon. Expect longer engine life, longer oil life, cleaner exhaust, and less fuel consumption. Lucas Oil. It works.