Oil Pump: Service and Repair

Engine Oil Pump Overhaul

Exploded View





Oil Pump Removal

1. Turn the crankshaft pulley so its top dead center (TDC) mark (A) lines up with the pointer (B).

2. Remove the oil pan. Engine Oil Pan Removal






3. Remove and discard the oil pump chain tensioner.






4. To hold the rear balancer shaft, insert a 6 mm long pin punch (Snap-on PPC 108 LA or equivalent) (A) into the maintenance hole in the lower balancer shaft holder and through the rear balancer shaft.

5. Loosen the oil pump sprocket mounting bolt.






6. Remove the oil pump sprocket (A), then remove the oil pump (B).






Oil Pump Inspection

1. Remove the pump housing.






2. Check the inner-to-outer rotor radial clearance between the inner rotor (A) and the outer rotor (B). If the inner-to-outer rotor radial clearance exceeds the service limit, replace the oil pump.










3. Check the pump housing-to-rotor axial clearance between the rotor (A) and the pump housing (B). If the pump housing-to-rotor axial clearance exceeds the service limit, replace the oil pump.










4. Check the pump housing-to-outer rotor radial clearance between the outer rotor (A) and the pump housing (B). If the pump housing-to-outer rotor radial clearance exceeds the service limit, replace the oil pump.





5. Inspect both rotors and the pump housing for scoring or other damage. Replace parts if necessary.






Balancer Shaft Inspection

1. Seat the balancer shaft by pushing it away from the oil pump sprocket end of the oil pump.

2. Zero the dial indicator against the end of the balancer shaft, then push the balancer shaft back and forth and read the end play.










3. Remove the pump housing.






4. Remove the baffle plate (A) and the upper balancer shaft holder (with bearings) (B), then remove the front balancer shaft (C) and the rear balancer shaft (D).






5. Measure the inner diameter of the No. 1 bearing for the front balancer shaft hole and the rear balancer shaft hole.





Front





Rear





6. Measure the diameters of the No. 1 journals on the front balancer shaft and the rear balancer shaft.





7. Clean both balancer shaft No. 2 journals and the bearing halves with a clean shop towel, then install the balancer shafts into the lower balancer shaft holder.

8. Place one strip of plastigage across each No. 2 journal.

Front





Rear





9. Reinstall the bearings and the upper balancer shaft holder, then tighten the bolts.
NOTE:

- Do not rotate the balancer shafts during inspection.

- After torquing, tighten the three 8 mm bolts extra 16 °.





10. Remove the upper balancer shaft holder and the bearings again, and measure the widest part with the plastigage. If the balancer shaft No. 2 journal oil clearance is out-of-tolerance, install new bearings, and recheck. If it is still out-of-tolerance, replace the balancer shafts.










11. Align the punch mark on the rear balancer shaft in the center of the two punch marks on the front balancer shaft, then install the balancer shafts on the lower balancer shaft holder.






12. Apply engine oil to the threads of the 8 mm bolts (A).
NOTE: After torquing, tighten the three 8 mm bolts extra 16 °.

13. Install the upper balancer shaft holder (B) and the baffle plate (C).






14. Install the pump housing.






Oil Pump Installation

1. Make sure the No. 1 piston top dead center (TDC) mark (A) lines up with the pointer (B).






2. Align the dowel pin (A) on the rear balancer shaft with the mark (B) on the oil pump.






3. To hold the rear balancer shaft, insert a 6 mm long pin punch (Snap-on PPC 108 LA or equivalent) (A) into the maintenance hole in the lower balancer shaft holder and through the rear balancer shaft.






4. Apply engine oil to the threads of the oil pump sprocket mounting bolt (A).

5. Loosely install the oil pump (B), then install the oil pump sprocket (C).

6. Tighten the oil pump mounting bolts and the oil pump sprocket mounting bolt.

7. Remove the long pin punch (D).






8. Squeeze the new oil pump chain tensioner (A), then install the set clip (B) on it as shown.
NOTE: The set clip is supplied with the oil pump chain tensioner.






9. Install the new oil pump chain tensioner.






10. Remove the set clip from the oil pump chain tensioner.

11. Install the oil pan. Engine Oil Pan Installation