Genuine OEM Audi Engine Thermostat, part number 059121111N. This vital component is responsible for precisely regulating the engine's operating temperature by controlling the flow of coolant. Maintaining the engine within its optimal temperature range is crucial for fuel efficiency, emissions control, and overall engine longevity. Weighing approximately 0.301 kg, it is typically housed within a durable plastic assembly. Choosing a genuine OEM thermostat ensures accurate temperature calibration, reliable opening and closing, and resistance to coolant chemicals, which are essential for preventing engine overheating or undercooling.