This is a genuine BMW rubber boot, part number 11 51 7 514 944. The number stamped on the part is 11517514944; BMW's catalog files it under the short number 7514944. You will find it on our Engine shelf, under Coolant pump with drive.
It fits every E46 body style (316i, 316ti, 318i and 318ti, 2001–2004), with the N40, N42, N45 or N46 engines.
BMW draws it on the Waterpump - Thermostat (11_3192) diagram. It also comes in BMW kit Gasket Set Engine Block Asbesto Free (7511529).
We have not had one on the shelf yet. Request it and we will tell you when one comes off a car.