CRC Industries' K&W Fiberlock head gasket & block repair comes as a pour-and-go product that permanently repairs cracks in head gaskets, engine blocks, freeze plugs, cylinder heads and radiators. Designed to be a permanent pour-in repair additive, this product provides a permanent seal without any flushing. Engineered with sodium silicate reinforced with military-strength proprietary fibers, the sealant forms an interlocking web-like weave over the crack or breach, creating a permanent, multi-layer repair. Comes with a "double your money back" guarantee.