This manual covers the International Harvester BD144, BD154, D188, D239, and DT239 diesel engines. These 4-cylinder diesel engines, with displacements ranging from 144 to 239 cubic inches, were designed for robust performance in various applications. The DT239 model features a turbocharger, while other models typically do not. These engines powered a wide array of International Harvester equipment, including tractors such as the B-275, B-414, 424, 2424, 3414, 3444, 444, 2504, 3514, 544, 2544, 574, 664, and 674, as well as windrowers and forklifts. This Illustrated Parts Manual Catalog provides essential information for the disassembly, repair, reassembly, servicing, rebuilding, and parts ordering for these International Harvester engines. It includes detailed illustrations and exploded views to aid in identification and understanding of components. The manual is designed to be a valuable resource for owners, mechanics, and technicians, enabling informed parts ordering, saving time, and reducing costs associated with maintenance and repair. The English language manual is searchable and indexed for efficient navigation.