Overheating can sometimes be caused by a cracked engine block, leaks from the cooling system, coolant leaking past the head gasket. A crack in the engine block could be an expensive repair, but with K&W FiberLock Head Gasket & Block Repair you can be back on the road in 20 minutes. K&W FiberLock is the most advanced product for repairing cracked head gaskets and engine blocks. When there is a crack or hole in your block or cooling system, the pressure in the system causes heat to build up around the crack. FiberLock seeks out the hot spots and seals them permanently with three levels of protection. Military strength fibers create an interlocking web over the breach, nanoparticles fill in and create a solid bond to the metal and Cool-X conditioner keeps your engine running cooler long after the repair is made. FiberLock is compatible with all types of antifreeze.