Review on Bar's Leaks PLT11 Pelletized Heavy Duty Radiator Stop Leak - 11 oz. by Billy Reeves

Makes your coolant look like dirt but I use it on all the older cars I work on the cooling system. In my opinion this is great for preventative maintenance, especially for damaged systems which may have rust as they contain oil. lag and then take a couple of weeks to complete the process. Since then there have been no more problems with overheating. After a few days of idling I noticed a small stain from the radiator. A few months later I still haven't had to add water or replace the radiator. I wouldn't rely on it to fix a head gasket, but I highly recommend using it for small leaks and as a preventive measure.