Abstract: A cast iron cylinder liner for use in an engine block. The liner is cast to have a number of longitudinal grooves and machined to have a number of intersecting annular grooves to create an inverted waffle-like pattern of ridges and grooves on the outer circumferential surface of the liner. This pattern significantly increases the surface area through which cooling of the liner occurs and, thus, increases the liner's cooling capacity by approximately 30 to 40 percent. In addition, the pattern of ridges and grooves acts as a locking mechanism whereby the liner will not move within the cylinder block.