The Komatsu 12 Series, encompassing models D65E-12, D65P-12, D65EX-12, and D65PX-12, represents a robust line of equipment engineered for demanding operational environments. These machines are built upon a foundation of reliability and performance, featuring powerful diesel engines such as the 12.5 L S6D125-2, SAA6D125-2, and others, each delivering approximately 220 horsepower. With their substantial operating weight, hydrostatic steering systems, and multi-speed transmissions, these dozers are designed for heavy-duty earthmoving and construction tasks, offering durability and efficiency in their intended applications. This comprehensive Workshop and Engine Manual provides essential information for the maintenance and repair of your Komatsu 12 Series equipment. It details critical procedures, technical specifications, and diagnostic guidance for the various engine models and the hydrostatic steering system. By following the instructions within this English-language manual, owners, mechanics, and technicians can ensure optimal performance, longevity, and safety of the machinery, covering everything from routine servicing to in-depth troubleshooting.