This shop manual provides detailed service and repair instructions for the Komatsu 4D98, 4D106, and S4D106 diesel engines. It includes comprehensive procedures for diagnosing, troubleshooting, and repairing key components of these engines. The manual offers step-by-step guidance on disassembly, inspection, reassembly, and adjustments, supported by detailed diagrams and technical specifications. It covers maintenance schedules, proper handling techniques, and safety protocols to ensure optimal engine performance and longevity. This document is essential for mechanics and technicians to conduct accurate maintenance and repairs on Komatsu 4D98, 4D106, and S4D106 engines.