RB20/25/26/30 Water PumpNPW Water pumps are a high quality water pump that is Made In Japan to OEM specs and also include a waterpump gasket and water pump pulley stud kit. These units suit the following engines: RB20 RB25 RB26 RB30 Important Information: RB26, RB30 and RD28 all use non slotted, and the other RB engines use slotted. Although slotted is universal most of the time, casting irregularities can cause a small leak though the M6 hole.