This manual covers the Komatsu 108 Series Diesel Engine, a robust and reliable power unit designed for a wide range of applications including vehicles, heavy equipment, and industrial uses. Engineered for durability and performance, the 108 Series embodies Komatsu's commitment to quality, providing efficient operation and long service life across diverse operational environments. Its advanced diesel technology ensures consistent power delivery and fuel efficiency, making it a trusted choice for demanding tasks. The purpose of this English-language Service Repair Manual is to provide comprehensive technical information for operations performed in a service workshop. It details maintenance standards, repair procedures for key components such as valve seats, crankshaft bearings, and engine seals, and reconditioning processes like cylinder head grinding and valve grinding. The manual includes troubleshooting guides, performance testing data, and diagnostic features, supported by detailed illustrations, numbered instructions, and a structured table of contents to facilitate easy information retrieval for owners, mechanics, and technicians.