Manual - Chapter 5 - Fuel & Oil

23: Oil pump: removal, examination and refitting

  1. The oil pump is the rear part of a combined oil/water pump assembly which is removed as follows:
  2. Drain the engine oil as described in Routine Maintenance, then drain the coolant. See Chapter 4 - Cooling - Draining. Disconnect the oil pressure switch lead from the switch and remove the radiator bottom hose.
  3. Remove the pump cover retaining screws and withdraw the cover, then remove the pump body retaining screws and withdraw the pump body; a few gentle taps with a soft-faced mallet should break the joint seal. Note the 0-ring sealing the coolant passage between the pump and the crankcase lower section, also the 0-ring around the pump drive shaft rear end; both should be renewed whenever they are disturbed.
  4. Withdraw the pump drive shaft; if the pump shaft is to be removed, or either of the pump seals are to be renewed, refer to Chapter 4 - Cooling - Water pump: removal, renovation and refitting.
  5. Closely examine all gear teeth mating surfaces and the body casting; if any component is seen to be worn or damaged in any way it must be renewed. Since there are no service limits specified, pump wear cannot be checked by direct measurement; the only possible test of the lubrication system is a test of the operating pressure which will require a pressure gauge and the necessary adaptors.
  6. On reassembly, thoroughly clean all components in the pump body, including the pressure relief valve and pressure switch. Blow clear all oilways with compressed air and refit the various components.
  7. Fit a new 0-ring around the coolant passage and to the pump drive shaft rear end. Apply a thin smear of Three Bond 1207 B sealant to the pump/crankcase mating surfaces and refit the pump assembly, ensuring that the drive shaft engages correctly in the output shaft.
  8. Rotate the crankshaft to centralise the pump gears while 'lightening the pump body mounting screws to the specified torque setting (where given). Connect the oil pressure switch lead to the switch terminal and carefully refit the switch cover. Apply a thin smear of Three Bond 1 207 B sealant to the mating surfaces and refit the pump front cover, tightening its retaining screws to the specified torque wrench setting, where given.
  9. Refill the cooling system (Chapter 4 - Cooling system: filling). Replenish the engine with oil as described in Routine Maintenance - Check the engine oil level, then refit all other disturbed components.


23.4a Withdraw pump drive shaft


23.4b Water pump must be dismantled to permit removal of pump driven shaft


23.5 Clean all pump components thoroughly and check for wear


23.7 Do not forget to renew 0-rings on refitting oil/water pump assembly