See Figures 1 through 7
- Remove the oil pan, as described in the previous procedure.
- Remove the oil pump retainer bolts, then remove the oil pump along with the drive shaft.
CLEANING AND INSPECTION
Only the 4.0L engine oil pumps are serviceable. Do not disassemble any of the other oil pumps. If the other oil pumps are defective, simply replace the entire assembly with a new one.4.0L Engine
- Remove the oil pump from the engine.
- If not already done, lift the oil pump intermediate shaft out of the pump.
- Remove the two screws, then remove the oil pump screen cover and tube.
- Remove the cover attaching bolts, then remove the cover.
- Remove the inner rotor and shaft assembly, then remove the outer race.
- Drill a small hole and insert a self-threading sheet metal screw of the proper diameter into the oil pressure relief valve chamber cap. Pull the cap out of the chamber.
- Remove the spring and plunger from the oil pump.
- Clean all parts in solvent, then dry them thoroughly with compressed air. Use a brush to clean the inside of the pump housing and pressure relief valve chamber; make sure all dirt and metal particles are removed.
- Look for deep scoring in the cover. Light concentric scratches only indicate that the pump has been used and are acceptable. If the cover is deeply scored, replace the entire oil pump.
- Examine for scoring or wear on the shaft. If such damage is exhibited, replace the oil pump.
- Inspect the rotor for burrs or score marks. If excessive burrs or scoring is evident, replace the oil pump with a new one.
- Remove minor imperfections from parts with an oil stone.
- Using a straightedge and feeler gauge, make sure the inside of the cover is flat. If the cover is warped 0.0015 in. (0.038mm) or more, replace the oil pump with a new one.
- Insert the inner and outer rotor into the oil pump housing.
- Place a straightedge over the rotor assembly and housing.
- Measure the clearance between the straightedge and the inner rotor, then the outer rotor. The clearance must not exceed 0.004 in. (0.10mm). If the clearance is excessive, replace the oil pump.
- Using a feeler gauge, measure the clearance between the outer rotor (race) and the housing.
- The specification is 0.001-0.013 in. (0.025-0.33mm). If the clearance is excessive, replace the oil pump unit.
- Inspect the valve plunger for scoring and free operation. Light scratches may be removed with crocus cloth.
- Inspect the valve spring for breaks, cracks, tilting and collapsed coils. If any are evident, replace the oil pump spring.
- Using TOOL-6513-DD, check the valve spring tension. The correct valve spring tension should be 13.6-14.7 lbs. at 1.39 in. spring height (60.5-65.4 N at 35.31mm). If the spring is too weak, replace it with a new one.
- Using a plug gauge, measure the regulator valve bore.
- Using a micrometer, measure the outside diameter of the plunger.
- Subtract the plunger diameter from the bore size. The allowable clearance is 0.0015-0.0030 in. (0.038-0.076mm). If the clearance is excessive, replace the oil pump with a new one.
- Prime the oil pump with clean engine oil by filling either the inlet or outlet port with engine oil. Rotate the pump shaft to distribute the oil within the pump body.
- Insert the oil pump intermediate shaft into the block with the pointed end facing inward. The pointed end is closest to the pressed-on flange.
- Install the pump and tighten the mounting bolts to 14-21 ft. lbs. (19-28 Nm) on 2.3L engines, to 6-10 ft. lbs. (9-13 Nm) on 2.8L engines, to 30-40 ft. lbs. (40-55 Nm) on 3.0L engines, and to 13-15 ft. lbs on 4.0L engines.
- Clean and install the oil pump screen cover and tube with an oil pump inlet tube gasket. Tighten the bolts to 7-10 ft. lbs. (9-13 Nm).
- Install the oil pan, as described in the previous procedure.