Oil Pump: Service and Repair

OIL PUMP

REMOVAL
1. Disconnect the battery negative cables.
2. Remove fan/drive assembly.
3. Remove the accessory drive belt.
4. Remove the fan support/hub assembly.
5. Remove crankshaft damper and speed indicator ring.
6. Remove hydraulic pump.
7. Remove accessory drive belt tensioner.
8. Remove the gear housing cover.





9. Remove the four mounting bolts and pull the oil pump from the bore in the cylinder block (Fig. 116).

CLEANING
Clean all parts in solvent and dry with compressed air. Clean the old sealer residue from the back of the gear housing cover and front of the gear housing.

INSPECTION
Disassemble and inspect the oil pump as follows:
1. Visually inspect the lube pump gears for chips, cracks or excessive wear.





2. Remove the back plate (Fig. 117).
3. Mark TOP on the gerotor planetary using a felt tip pen (Fig. 117).
4. Remove the gerotor planetary (Fig. 117). Inspect for excessive wear or damage. Inspect the pump housing and gerotor drive for damaged and excessive wear.
5. Install the gerotor planetary in the original position.





6. Measure the tip clearance (Fig. 118). Maximum clearance is 0.1778 mm (0.007 in.). If the oil pump is out of limits, replace the pump.





7. Measure the clearance of the gerotor drive/gerotor planetary to port plate (Fig. 119). Maximum clearance is 0.127 mm (0.005 in.). If the oil pump is out of limits, replace the pump.





8. Measure the clearance of the gerotor planetary to the body bore (Fig. 120). Maximum clearance is 0.381 mm (0.015 in.). If the oil pump is out of limits, replace the pump.





9. Measure the gears backlash (Fig. 121). The limits of a used pump is 0.15 - 0.25 mm (0.006 - 0.010 in.). If the backlash is out of limits, replace the oil pump.
10. Install the back plate.

INSTALLATION
1. Lubricate the pump with clean engine oil. Filling the pump with clean engine oil during installation will help to prime the pump at engine start up.





2. Install the pump (Fig. 116). Verify the idler gear pin is installed in the locating bore in the cylinder block. Tighten the oil pump mounting bolts in two steps, in the sequence shown in (Fig. 122).
- Step 1-Tighten to 8 Nm (71 in. lbs.) torque.
- Step 2-Tighten to 24 Nm (18 ft. lbs.) torque.
3. The back plate on the pump seats against the bottom of the bore in the cylinder block. When the pump is correctly installed, the flange on the pump will not touch the cylinder block.





4. Measure the idler gear to pump drive gear backlash and the idler gear to crankshaft gear backlash (Fig. 123). The backlash should be 0.15 - 0.25 mm (0.006 - 0.010 in.). If the backlash is out of limits, replace the oil pump.
5. If the adjoining gear moves when you measure the backlash, the reading will be incorrect.
6. Apply a bead of Mopar Silicone Rubber Adhesive Sealant or equivalent to the gear housing cover sealing surface.
7. Install the gear housing cover.
8. Install the vibration damper and speed indicator ring.
9. Install the fan support/hub assembly and torque bolts to 32 Nm (24 ft. lbs.).
10. Install hydraulic pump.
11. Install accessory drive belt tensioner. Torque bolt to 43 Nm (32 ft. lbs.).
12. Install the accessory drive belt.
13. Install the cooling fan.
14. Connect battery negative cables.
15. Start engine and check for oil leaks.