Genuine OEM Mercedes-Benz Radiator Drain Plug Seal, part number A0005010176. This small but vital seal is designed to create a watertight barrier when the radiator drain plug is installed. Its primary function is to prevent coolant from leaking out of the cooling system during maintenance or normal operation. A proper seal is essential for maintaining the correct coolant level and preventing overheating. Genuine OEM parts offer the correct material composition and dimensions for a reliable seal.