STP Oil Treatment (15 oz.)

Inside this 15-ounce bottle is STP Oil Treatment, a high-viscosity oil additive that contains ZDDP (Zinc Dialkyl Dithiophosphate) as its active anti-wear agent. ZDDP works by creating a protective film on metal surfaces inside the engine, reducing direct metal-to-metal contact at critical wear points like cam lobes, lifters, and bearing surfaces.

The high-viscosity formula provides a thicker cushion between moving engine parts compared to the base motor oil alone. This added film strength helps reduce friction, which is one of the major contributors to heat buildup and premature wear inside the engine. STP also states the treatment helps reduce oil consumption in engines that burn or use oil between changes. The formula works with both conventional and synthetic motor oils and is compatible with all gasoline-powered cars, light trucks, and SUVs.

Usage is simple: add one bottle to four to five quarts of oil at your next oil change or between changes. The ZDDP additive is especially relevant for older engines with flat-tappet camshafts, which rely heavily on this type of anti-wear chemistry.