The locking spring washer with code 06.16169-0004.2 is a crucial safety component used in bolted connections within the MAN L21/31 engine. Designed to prevent nuts and bolts from loosening under vibration and thermal expansion, this washer exerts a continuous tension against the fastener head. Its split-ring, spring-like design provides reliable anti-rotation performance, making it essential in securing structural and dynamic parts in both marine propulsion and stationary engine applications.