Go to www.realoem.com and enter the last 7 characters of the car's VIN. Hit enter and bookmark the page. Cooling system parts are in the engine and radiator sections. I bought OE parts from FCP Euro for my E46. OE means the part is made by the same manufacturer that supplies the part to BMW. OEM means the part was made by a manufacturer of parts for BME but does not supply this part to BMW.