Sierra International 18-0587 Oil Seal The Sierra 18-0587 Oil Seal is interchangeable with the following: Mallory 9-76414, Yamaha 93101-25M03-00. Each Sierra product meets or exceeds the original equipment part it replaces. Sierra Oil Seal ID: 24mm, OD: 40.25mm, Width: 6mm Sierra part number: 18-0587 Interchangeable with the following: Mallory 9-76414, Yamaha 93101-25M03-00