Bars Leaks Liquid Copper Block Seal Intake & Radiator Stop Leak seals larger leaks regular stop leaks wont.  One step formula permanently repairs coolant loss problems on cars, trucks, vans, SUVs and RVs.  Antifreeze compatible sodium silicate liquid glass penetrates large and small leaks in plastic, aluminum and cast iron heads, blocks, intake manifold & gaskets, freeze plugs, heater cores and radiators.  Fiber additives lock together with liquid to increase strength and promote a permanent seal.  It will not harm the cooling system when used properly, no draining is required.  Use with ALL types of traditional or extended life coolant including yellow, orange, pink, red, blue, purple and green silicate based & non-silicate based (OAT/HOAT) 50-50 mix antifreeze, and/or water.