This workshop service repair manual covers the Yanmar 6LYA-UTE and 6LYA-STE diesel engines. These inline 6-cylinder engines are turbocharged and intercooled, designed for robust performance in various applications. The 6LYA-UTE model offers approximately 300 mhp, while the 6LYA-STE provides around 315 mhp, both at 2100 rpm. With a displacement of 6.478 L, these engines are engineered for reliability and efficiency, featuring advanced systems such as direct injection common rail or mechanical injection, water-cooled operation, and forced lubrication. This comprehensive manual provides essential information for maintaining and repairing your Yanmar engine. It includes detailed step-by-step procedures, troubleshooting guides, technical specifications, and safety guidelines. Coverage extends to key maintenance areas including the fuel injection equipment, intake and exhaust systems, lubrication and cooling water systems, and the electrical system. With included diagrams, wiring diagrams, illustrations, and photos, this manual is an indispensable resource for owners, mechanics, and technicians to ensure optimal performance and longevity of the Yanmar 6LYA-UTE and 6LYA-STE engines.