MAHLE Original TX 144 78D Engine Coolant Thermostat Every MAHLE Original thermostat insert is designed to vehicle manufacturers' (OE) specifications - This thermostat insert is the OE part number for this application MAHLE Original thermostat inserts ensure that the engine reaches its operating temperature as quickly as possible and the optimum temperature is maintained The last two or three digits of the MAHLE Original thermostat insert part number represent the opening temperature of the thermostat insert in degrees Celsius