Oil pump - removal, inspection and refitting

In-car engine repair procedures / Oil pump - removal, inspection and refitting

Removal
Note: While this task is theoretically possible when the engine is in place in the vehicle, in practice, it requires so much preliminary dismantling, and is so difficult to carry out due to the restricted access, that owners are advised to remove the engine from the vehicle first. Note, however, that the oil pump pressure relief valve can be removed with the engine in situ - see paragraph 8.

In addition to the new pump gasket and other replacement parts required, read through Section 15, and ensure that the necessary tools and facilities are available.

1 Remove the timing belt (see Section 10).

2 Withdraw the crankshaft toothed pulley and the thrustwasher behind it, noting which way round the thrustwasher is fitted (see Section 11).

3 Remove the sump (see Section 15).

4 Undo the screws securing the oil pump pick-up/strainer pipe to the pump, then unscrew the nut and withdraw the oil pump pick-up/strainer pipe. Discard the gasket.

5 Unbolt the pump from the cylinder block/crankcase (see illustration). Withdraw and discard the gasket, and remove the crankshaft right-hand oil seal. Thoroughly clean and degrease all components, particularly the mating surfaces of the pump, the sump, and the cylinder block/crankcase.

16.5 Unscrew bolts (arrowed) to remove oil pump

Inspection
6 Unscrew the Torx screws, and remove the pump cover plate; noting any identification marks on the rotors, withdraw the rotors (see illustration).

16.6 Withdrawing oil pump inner rotor

7 Inspect the rotors for obvious signs of wear or damage, and renew if necessary; if either rotor, the pump body, or its cover plate are scored or damaged, the complete oil pump assembly must be renewed.

8 The oil pressure relief valve can be dismantled, if required, without disturbing the pump. With the vehicle parked on firm level ground, apply the handbrake securely and raise its front end, supporting it securely on axle stands. Remove the front right-hand roadwheel and auxiliary drivebelt cover (see Chapter 1) to provide access to the valve.

9 Unscrew the threaded plug, and recover the valve spring and plunger (see illustrations). If the plug’s sealing O-ring is worn or damaged, a new one must be obtained, to be fitted on reassembly.

16.9A Unscrew threaded plug - seen through right-hand wheel arch . . .

16.9B . . . to withdraw oil pressure relief valve spring and plunger

10 Reassembly is the reverse of the dismantling procedure; ensure the spring and valve are refitted the correct way round, and tighten the threaded plug securely.

Refitting
11 The oil pump must be primed on installation, by pouring clean engine oil into it, and rotating its inner rotor a few turns.

12 Using grease to stick the new gasket in place on the cylinder block/crankcase, and rotating the pump’s inner rotor to align with the flats on the crankshaft, refit the pump and insert the bolts, tightening them lightly at first (see illustration).

16.12 Use new gasket when refitting oil pump

13 Using a suitable straight edge and feeler gauges, check that the pump is both centred exactly around the crankshaft, and aligned squarely so that its (sump) mating surface is exactly the same amount - between 0.3 and 0.8 mm - below that of the cylinder block/ crankcase on each side of the crankshaft (see illustration). Being careful not to disturb the gasket, move the pump into the correct position, and tighten its bolts to the specified torque wrench setting.

16.13 Check the oil pump is positioned correctly

14 Check that the pump is correctly located; if necessary, unbolt it again, and repeat the full procedure to ensure that the pump is correctly aligned.

15 Fit a new crankshaft right-hand oil seal (see Section 20).

16 Using grease to stick the gasket in place on the pump, refit the pick-up/strainer pipe, tightening its screws and nut to their specified torque wrench settings (see illustration).

16.16 Use new gasket when refitting oil pick-up pipe to pump

17 The remainder of reassembly is the reverse of the removal procedure, referring to the relevant text for details where required.