OWS 420 Radiator Stop Leak The OWS 420 Radiator Stop Leak works by pressure and it contains a special compound that can block up to 20 holes in the radiator and allow the car to function as normal until permanent repairs can be rendered. USES: -Safeguards the radiator -Loss of coolant -Small seepage in cooling system -Leaking head gasket -Prevents future leaks   Our flagship product, the Vitamins For Your Car ® series, was developed at great expense and as such, we are proud to say that few can equal the outstanding performance and value that this product line offers. Vitamins For Your Car ® is a professional grade series of products specially formulated to keep automotives running with optimal effectiveness and efficiency. It focuses on three main areas, namely cleaning, protection and enhancement.