The self-locking nut K 32381 is an important securing component used in the barring-engine mechanism of the Adriadiesel/Jugoturbina/Zgoda/Sulzer ZV40/48 engine. The barring system is used to rotate the engine slowly during inspection, maintenance, preparation for operation, and other service procedures, making secure positioning of its mechanical components particularly important. The K 32381 nut provides a dependable threaded connection while incorporating a locking function intended to resist loosening under vibration, repeated engagement, mechanical loading, and movement of the barring mechanism. Maintaining correct fastening helps preserve alignment and prevents unwanted displacement that could interfere with smooth engagement or increase wear on neighboring components. The nut and its mating threads should therefore be inspected during appropriate maintenance for wear, thread damage, deformation, or deterioration of the locking function, with replacement where its secure locking performance can no longer be assured. By maintaining a reliable fastening within the barring-engine assembly, the K 32381 self-locking nut contributes to controlled barring operation, mechanical safety, reduced risk of component damage, and dependable servicing of the ZV40/48 engine.