This workshop service repair manual covers the Detroit Diesel 55 Series, specifically the 12.0L 6-cylinder in-line, 4-cycle, turbo-charged diesel engine. Engineered for robust performance and reliability, this engine is designed for demanding applications where power and durability are paramount. Its advanced turbo-charging system ensures efficient power delivery and optimal fuel economy, making it a trusted choice for heavy-duty operations. This comprehensive manual provides detailed information essential for the maintenance, repair, and servicing of the Detroit Diesel 55 Series engine. It includes extensive sections on general information, engine systems, component overhauls, electrical equipment, tune-up procedures, and troubleshooting. With over 1500 pages of detailed instructions, diagrams, and specifications, this manual is an indispensable resource for professional mechanics and owner-operators seeking to maintain their engine's peak performance and longevity.