The quality specification document, code 10.09004-5200-1.0, for the MAN L21/31 four-stroke engine is a critical technical reference that outlines the exact standards and tolerances required during manufacturing and servicing. It ensures that each component meets MAN Diesel's rigorous performance, material, and dimensional criteria, contributing to engine safety, durability, and reliability. This document is indispensable for quality assurance teams, service engineers, and suppliers working with original or replacement parts.