Genuine OEM Volkswagen Coolant Regulator Housing With Thermostat, part number 03L121111AM. This unit is crucial for regulating the flow of coolant within the engine system, maintaining the engine's optimal operating temperature. It is typically located on the engine block or cylinder head. Constructed from durable, heat-resistant plastic, this housing weighs approximately 0.305 kg. Choosing a genuine OEM part ensures precise fitment, proper sealing, and reliable temperature control, which is vital for engine longevity and efficiency.