Any sort of sealer in a cooling system is a "Band-Aid on a brain tumor" situation- - - -it does nothing to solve the problem- - - -it just hides the symptoms. Bar's Leaks is a vegetable fiber based sealer. Atomized powder sealers plug the leak with finely powdered metallic particles, either copper or aluminum, usually. Both have water-soluble glue as a carrier. Vegetable fiber is much less likely to clog radiator passages than metal, at least in my experience of almost 60 years of seeing the results of both products being used. A radiator repairman who is afraid to take one tank off a radiator and rod it out, then repair whatever leaks the process creates, is either incompetent or lazy, or maybe both. The modern design aluminum/plastic radiators are throwaway items, and most shops refuse to even attempt to repair them, other than maybe replacing a cracked plastic end tank. Even then, they run a risk of breaking off the crimped aluminum tabs that hold the tanks on. Soldering a leak in an aluminum core- - - -forget it!
Jerry
