Engine Oil Stop Leak 12 Ounce

PERMATEX Engine Oil Stop Leak is a 12-ounce motor oil additive engineered to seal small leaks and seeps in crankshaft seals, valve covers, oil pans, and gaskets without requiring engine teardown. Built for operators in high-mileage vehicles—whether civilian fleet maintenance, law enforcement patrol units, or military support equipment—this additive addresses slow oil weeps that accelerate component wear and create maintenance headaches in the field. A single 12 oz bottle treats one engine, making it an economical first-line solution before costlier mechanical repair becomes necessary.

The formula works by conditioning rubber seals and gaskets to restore elasticity and reduce permeability, effectively shrinking micro-gaps where oil escapes. PERMATEX's proprietary blend contains seal-conditioning agents that soften hardened elastomers without thinning the oil or affecting engine performance, viscosity, or sump capacity. Compatible with conventional, synthetic, and semi-synthetic motor oils, the additive mixes seamlessly once poured into the crankcase and begins conditioning seals within normal operating cycles. This approach avoids invasive engine work, prolonging seal life and maintaining oil pressure integrity in engines experiencing early-stage weeping.

Mechanics, fleet supervisors, and vehicle owners managing aging equipment benefit from Engine Oil Stop Leak's non-invasive intervention window—ideal when minor seeps first appear but before major gasket replacement is justified. Application is straightforward: pour the entire 12 oz bottle into the oil filler cap at the next scheduled oil check or maintenance interval. Results typically appear within 200–300 miles of driving as seal conditioning takes effect. Not a substitute for failed seals or severe leaks, this additive performs best on gradual weeps in vehicles with solid mechanical condition otherwise.