BMW e60 e63 Water Hose from Expansion Tank (Upper Fitting) Water Hose from Expansion Tank (Upper Fitting) Brand NEW part with full 1 year warranty. BMW part# 17 12 7 521 775, note the mid-year splits. Genuine BMW part, recently made: not been lying around. PLEASE NOTE the mid-year split on PRODUCTION date. See Models Chart BELOW. Not sure about your car? email us your VIN to confirm.