Oil Pump: Service and Repair

REMOVAL
1. Remove the oil pan and pick-up tube.
2. Remove the timing chain cover.
3. Remove the timing chains and tensioners.
4. Remove the four bolts, primary timing chain tensioner and the oil pump.

DISASSEMBLY
1. Remove oil pump cover screws and lift off cover plate.
2. Remove pump inner and outer rotors.

NOTE: Once the oil pressure relief valve, cup plug, and pin are removed, the pump assembly must be replaced.

3. If it is necessary to remove the pressure relief valve, drive the roll pin from pump housing and remove cup plug, spring and valve.

CLEANING
1. Wash all parts in a suitable solvent.

INSPECTION

CAUTION: Oil pump pressure relief valve and spring should not be removed from the oil pump. If these components are disassembled and or removed from the pump the entire oil pump assembly must be replaced.

1. Clean all parts thoroughly. Mating surface of the oil pump housing should be smooth. If the pump cover is scratched or grooved the oil pump assembly should be replaced.





2. Lay a straight edge across the pump cover surface (Fig. 106). If a 0.025 mm (0.001 inch) feeler gauge can be inserted between the cover and the straight edge the oil pump assembly should be replaced.





3. Measure the thickness of the outer rotor (Fig. 107). If the outer rotor thickness measures at 12.005 mm (0.472 inch) or less the oil pump assembly must be replaced.
4. Measure the diameter of the outer rotor. If the outer rotor diameter measures at 85.925 mm (3.382 inch) or less the oil pump assembly must be replaced.





5. Measure the thickness of the inner rotor (Fig. 108). If the inner rotor thickness measures at 12.005 mm (0.472 inch) or less then the oil pump assembly must be replaced.





6. Slide outer rotor into the body of the oil pump. Press the outer rotor to one side of the oil pump body and measure clearance between the outer rotor and the body (Fig. 109). If the measurement is 0.235 mm (0.009 inch) or more the oil pump assembly must be replaced.





7. Install the inner rotor in the into the oil pump body. Measure the clearance between the inner and outer rotors (Fig. 110). If the clearance between the rotors is 0.150 mm (0.006 inch) or more the oil pump assembly must be replaced.





8. Place a straight edge across the body of the oil pump (between the bolt holes), if a feeler gauge of 0.095 mm (0.0038 inch) or greater can be inserted between the straightedge and the rotors, the pump must be replaced (Fig. 111).

NOTE: The 4.7 Oil pump is released as an assembly. There are no Diamler Chrysler part numbers for Sub-Assembly components. In the event the oil pump is not functioning or out of specification it must be replaced as an assembly.

ASSEMBLY
1. Wash all parts in a suitable solvent and inspect carefully for damage or wear.
2. Install inner and outer rotors
3. Install oil pump cover plate and install cover bolts and tighten them to 12 Nm (105 in. lbs.).
4. Prime oil pump before installation by filling rotor cavity with engine oil.
5. If oil pressure is low and pump is within specifications, inspect for worn engine bearings or other causes for oil pressure loss.

INSTALLATION
1. Position the oil pump onto the crankshaft and install two oil pump retaining bolts.
2. Position the primary timing chain tensioner and install the two retaining bolts.





3. Tighten the oil pump and primary timing chain tensioner retaining bolts to 28 Nm (250 in. lbs.) in the sequence shown (Fig. 112).
4. Install the secondary timing chain tensioners and timing chains.
5. Install the timing chain cover.
6. Install the pick-up tube and oil pan.