The lock washer, code 06.16169-0003.0, is an essential securing element used throughout the MAN L21/31 engine to prevent the loosening of bolted joints under vibration and dynamic mechanical loads. Designed with a specific geometry that creates additional friction and mechanical resistance, it ensures that fasteners maintain their required preload during long operating cycles. Even though small in size, the lock washer plays a crucial role in maintaining structural integrity and operational safety within complex engine assemblies. Manufactured from durable, fatigue-resistant materials, it provides consistent locking performance and supports reliable engine operation in demanding marine and stationary power applications.