Genuine OEM Volkswagen Crankshaft, part number 03L105021A. The crankshaft is a central component of the engine, converting the reciprocating motion of the pistons into rotational motion that ultimately drives the vehicle's wheels. It is precisely balanced and manufactured to withstand extreme forces and temperatures within the engine. Genuine OEM crankshafts ensure the correct geometry, material strength, and bearing surface finish for smooth, reliable engine operation and longevity.