The lock washer with code 06.16169-0003.0 is a compact but essential component in the MAN L21/31 engine, designed to prevent loosening of fasteners under dynamic loads. Its toothed or serrated structure bites into the mating surfaces, offering mechanical resistance against vibration-induced rotation. This washer ensures that bolts and nuts remain securely fastened, thereby safeguarding the stability of critical engine joints and assemblies during prolonged operation.