The lock washer, code 06.16169-0003.0, is an important securing element designed to prevent loosening of bolted connections in the MAN L21/31 engine under vibration and dynamic load conditions. Its specialized geometry creates additional friction and mechanical resistance, ensuring that fasteners maintain consistent preload throughout prolonged operation. By safeguarding against self-rotation and loss of clamping force, the lock washer protects critical engine assemblies and reduces the risk of unplanned downtime. Manufactured from durable, fatigue-resistant materials, it delivers reliable performance and enhances operational safety in marine and stationary power applications.