Genuine OEM Volkswagen Bolt With Washer, part number WHT011020. This threaded fastener with a head and an integrated washer is used to secure the coolant cooler assembly. It is located at position 9 in the diagram. The integrated washer provides a larger surface area for load distribution. Genuine OEM bolts are manufactured to precise specifications, ensuring proper thread engagement and material strength for the secure mounting of the engine cooling system components.