Genuine OEM Audi Engine Thermostat O-Ring Gasket, part number 032121119H. This sealing ring is designed to create a tight, leak-free seal for the engine thermostat housing. It is critical for preventing coolant leaks and ensuring the thermostat operates correctly to regulate engine temperature. The O-ring measures approximately 55mm in diameter and 3mm in thickness. Using genuine OEM O-rings ensures the correct material composition and precise dimensions, guaranteeing a reliable and long-lasting seal against the demanding conditions of the engine cooling system.