Oil Pump: Service and Repair

OIL PUMP

REMOVAL
1. Disconnect negative battery cable.
2. Remove crankshaft damper.
3. Remove Timing Belt.
4. Remove Oil Pan.

Fig. 88:

5. Remove Crankshaft Sprocket using Special Tool 6793 and insert C-4685-C2 (Fig. 88).

6. Remove oil pick-up tube.
7. Remove oil pump, (Fig. 89) and front crankshaft seal.

DISASSEMBLY
1. To remove the relief valve, proceed as follows:

Fig. 89:

a. Remove the threaded plug and gasket from the oil pump (Fig. 89).
b. Remove spring and relief valve (Fig. 89).
2. Remove oil pump cover screws, and lift off cover.
3. Remove pump rotors.
4. Wash all parts in a suitable solvent and inspect carefully for damage or wear.

CLEANING
1. Clean all parts thoroughly in a suitable solvent.

INSPECTION

Fig. 90:

1. Clean all parts thoroughly. Mating surface of the oil pump should be smooth (Fig. 90). Replace pump cover if scratched or grooved.

Fig. 91:

2. Lay a straightedge across the pump cover surface (Fig. 91). If a 0.025 mm (0.001 inch) feeler gauge can be inserted between cover and straight edge, cover should be replaced.

Fig. 92:

3. Measure thickness and diameter of outer rotor. If outer rotor thickness measures 9.40 mm (0.370 inch) or less (Fig. 92), or if the diameter is 79.95 mm (3.148 inch) or less, replace outer rotor.

Fig. 93:

4. If inner rotor measures 9.40 mm (0.370 inch) or less replace inner rotor (Fig. 93).

Fig. 94:

5. Slide outer rotor into pump housing, press to one side with fingers and measure clearance between rotor and housing (Fig. 94). If measurement is 0.39 mm (0.015 inch) or more, replace housing only if outer rotor is in specification.

Fig. 95:

6. Install inner rotor into pump housing. If clearance between inner and outer rotors (Fig. 95) is 0.203 mm (0.008 inch) or more, replace both rotors.

Fig. 96:

7. Place a straightedge across the face of the pump housing, between bolt holes. If a feeler gauge of 0.102 mm (0.004 inch), or more can be inserted between rotors and the straightedge, replace pump assembly (Fig. 96), ONLY if rotors are in specifications.
8. Inspect oil pressure relief valve plunger for scoring and free operation in its bore. Small marks may be removed with 400 grit wet or dry sandpaper.
9. The relief valve spring has a free length of approximately 60.7 mm (2.39 inches) it should test between 18 and 19 pounds when compressed to 40.5 mm (1.60 inches). Replace spring that fails to meet specifications.
10. If oil pressure is low and pump is within specifications, inspect for worn engine bearings or other reasons for oil pressure loss.

ASSEMBLY
1. Assemble pump, using new parts as required. Install the inner rotor with chamfer facing the cast iron oil pump cover.
2. Prime oil pump before installation by filling rotor cavity with engine oil.
3. Install cover and tighten screws to 12 Nm (105 inch lbs.).

CAUTION: Oil pump pressure relief valve must be installed as shown in (Fig. 89) or serious damage may occur.

4. Install relief valve, spring, gasket and cap as shown in (Fig. 89). Tighten cap to 41 Nm (30 ft. lbs.).

INSTALLATION
1. Make sure all surfaces are clean and free of oil and dirt.

Fig. 97:

2. Apply Mopar Gasket Maker to oil pump as shown in (Fig. 97). Install oil ring into oil pump body discharge passage.
3. Prime oil pump before installation.
4. Align oil pump rotor flats with flats on crankshaft as you install the oil pump to the block.

NOTE: Front crankshaft seal MUST be out of pump to align, or damage may result.

Fig. 98:

5. Install new front crankshaft seal using Special Tool 6780 (Fig. 98).

Fig. 99:

6. Install crankshaft sprocket using Special Tool 6792 (Fig. 99).
7. Install oil pump pick-up tube.
8. Install oil pan.
9. Install Timing Belt.
10. Install crankshaft damper.
11. Replace oil filter.
12. Lower vehicle.
13. Fill engine crankcase with proper oil to correct level.
14. Connect negative battery cable.