Oil Pump: Service and Repair

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 (Fig. 156).





6. Remove the gear housing cover (Fig. 157).





7. Remove the four mounting bolts and pull the pump from the bore in the cylinder block (Fig. 158).

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. 159).
3. Mark TOP on the gerotor planetary using a felt tip pen (Fig. 159).
4. Remove the gerotor planetary (Fig. 159). 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. The chamfer must be on the O.D. and down.





6. Measure the tip clearance (Fig. 160). Maximum clearance is 0.1778 mm (0.007 inch). 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. 161). Maximum clearance is 0.127 mm (0.005 inch). If the oil pump is out of limits, replace the pump.





8. Measure the clearance of the gerotor planetary to the body bore (Fig. 162). Maximum clearance is 0.381 mm (0.015 inch). If the oil pump is out of limits, replace the pump.





9. Measure the gears backlash (Fig. 163). The limits of a used pump is 0.075 - 0.85 mm (0.0296 - 0.0335 inch). 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. Verify the idler gear pin is installed in the locating bore in the cylinder block.





3. Install the pump (Fig. 158). Tighten the oil pump mounting bolts in two steps, in the sequence shown in (Fig. 164).
^ Step 1-Tighten to 5 Nm (44 inch lbs.) torque.
^ Step 2-Tighten to 24 Nm (18 ft. lbs.) torque.
4. 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.





5. Measure the idler gear to pump drive gear backlash and the idler gear to crankshaft gear backlash (Fig. 165). The backlash should be 0.75 - 0.85 mm (0.0296 - 0.0335 inch). If the backlash is out of limits, replace the oil pump.
6. If the adjoining gear moves when you measure the backlash, the reading will be incorrect.
7. Apply a bead of Mopar Silicone Rubber Adhesive Sealant or equivalent to the gear housing cover sealing surface.
8. Install the gear housing cover.
9. Install the vibration damper.
10. Install the fan support/hub assembly and torque bolts to 24 Nm (18 ft. lbs.).
11. Install the accessory drive belt.
12. Install the cooling fan.
13. Connect battery negative cables.
14. Start engine and check for oil leaks.