As seen on Two Guys Garage on the SPEED channel: Cracked engine blocks and faulty head gaskets are expensive to fix and sometimes aren't worth repairing, depending on the value of your car. K&W FIBERLOCK from CRC Industries is a permanent fix for a cracked block or head gasket. You don't need to drain the cooling system, just Pour in the product and Go. The sodium silicate in FIBERLOCK is reinforced with military-strength fibers that create a web-like weave over the crack for a multi-layer repair. The pressure released towards the crack forces more product to the damaged area and allows FIBERLOCK to cure. Once it cures, the air in the cooling system helps the sodium silicate solidify, making it a permanent repair.