A cracked engine block can sometimes be repaired by welding, chemical sealants or metal stitching and epoxy. The choice of repair methods depends on the extent of the crack. Some cracks are not repairable, depending on the extent of the damage.
Gaining access to the engine block generally requires removing the engine, which must be done for assessment and repair preparation. Thorough cleaning of the crack is vital before any repair can be attempted. If the crack is less than 8 inches long and 1/8 inch wide it may be repairable using a metal stitching and epoxy kit. Metal stitches are inserted into the crack with a hammer and an engine block epoxy is used to fill the crack completely. Larger cracks may be repairable by welding, however welding cast iron is very difficult and requires an experienced welder with the proper skills and equipment.