With two applications this Clip 101235600 is the most specified part.
The component with the lowest price in the OIL PUMP schematic is the Gasket, Breather Bolt (nas).
Parts such as the Oil Pump: Clip, Gear, Worm Wheel, Clip 101235600, Circlip(1ey) are included in the Ew50 2003 5wk1 England 1b5wk-300f1 Oil Pump parts fiche.