Heavy duty sealer. Add to your engine oil. No. 1 Selling oil stop leak! For leak prevention. Now with anti-wear protection for cars; trucks; van; tractors; marine. Today's moters oil may not contain the lubrication needed to protect an older vehicle. CD-2 Heavy Duty Stop Leak not only stops oil leaks, it helps prevent sludge and vanish formation while preventing engine wear. Anti-wear and friction modifiers for maximum engine protection guaranteed to stop oil leak. Added detergents keeps oil cleaner longer, will not plug oil filter. Compatible will all types and grades of motor oil. Use in gasoline or diesel engines will not harm catalytic converters. Satisfaction Guaranteed.