They press in from the top. Machine shops charge around $100 per liner to replace. "Slipped" liners are common on later motors. From what I understand, the original liners are somewhat shorten than they should be. There is a lip at the bottom of the bore that the liners never contact. Replacement liners are longer, get pressed all the way down to the lip, and then get machined smooth with the top of the block. Slipped liners will move up and down inside the bore as the piston moves up and down causing a terrible knocking sound as it bounces off the cylinder head and the lower lip. The only way I know to remove a damaged liner is to bore it out.