Description Reviews MINI Cooper Oil Pump. Fits both Cooper and Cooper S, N16, N18 & the N18 JCW. It is a good idea to replace it when doing a full engine build to make sure your getting full and correct oil pressure. This is the best time to do an oil pump chain if your doing timing. We also sell the sprocket bolt that you will need since it is a one time use only bolt! This is a quality aftermarket pump.