I don’t know where this stuff has been all my life, but it’s the only stop leak I’ve ever used that really worked. And I’ve used a few. Thanks a million.Even though you guaranteed result, I really didn’t expect it to work, cause I had tried so many other products to stop the mother of all leaks. I would leak about 1/3 cup of oil every time I stopped my 96 Montero. The leaking started when I inadvertingly used synthetic oil in my regular oil change (lesson to others-never use synthentic oil on older car), and it began to pour oil. I tried all the products at the parts house with absolutely no slowdown, so I was buying kitty litter by the the carload for my driveway. I received your stopleak, changed the oil, added it to the crankcase, ran the engine for 10 minutes and let it sit overnight, the next morning I’d say that 90% of the leaking stopped. This morning 95% stopped. I put 3 oz in my other car at the same time for a minor valve cover leak, and it stopped it overnight too. Needless to say, I won’t be asking for my money back