- Disconnect the negative battery cable.
- Remove the valve covers, timing chain cover, and oil pan. Refer to the procedures in this section.
- Remove the timing chains according to the procedure in this section.
- Remove the 4 bolts retaining the oil pump to the cylinder block and remove the pump.
- Remove the 2 bolts retaining the oil pickup tube to the oil pump and remove the bolt retaining the oil pickup tube to the main bearing stud spacer. Remove the pickup tube.
5.0L and 5.8L Engines
- Disconnect the negative battery cable. Remove the oil pan; see the procedure in this section.
- Remove the oil pump inlet tube and screen assembly.
- Remove the oil pump attaching bolts and gasket. Remove the oil pump intermediate shaft.
INSPECTION AND OVERHAUL4.6L Engine
Internal components of the oil pump on the 4.6L engine are not serviceable. If the oil pump is suspect, the entire unit must be replaced.
5.0L and 5.8L Engines
- Disassemble the pump and wash all parts in solvent. Use a brush to clean the inside of the pump housing and the pressure relief valve chamber. Make sure all dirt and metal particles are removed. After washing, dry the parts with compressed air, if available.
- Check the inside of the pump housing and the inner and outer gears for damage or excessive wear.
- Check the mating surface of the pump cover for wear. Minor scuff marks are normal, but if the cover, gears or housing surfaces are excessively worn, scored or grooved, replace the pump. Inspect the rotor for nicks, burrs or score marks. Remove minor imperfections with an oil stone.
- Measure the inner to outer rotor tip clearance. With the rotor assembly removed from the pump and resting on a flat surface, the inner and outer rotor tip clearance must not exceed 0.012 in. (0.30mm) with the feeler gauge inserted 0.5 in. (13mm) minimum.
- With the rotor assembly installed in the housing, place a straightedge over the rotor assembly and the housing. Measure the rotor end-play between the straightedge and both the inner and outer race. The maximum clearance must not exceed 0.005 in. (0.13mm).
Inspect the relief valve spring to see if it is collapsed or worn. Check the relief valve spring tension. Specifications are as follows:
5.0L engine-10.6-12.2 lbs. @ 1.704 in.
- If the spring tension is not within specification and/or the spring is worn or damaged, replace the pump. Check the relief valve piston for free operation in the bore.
- If inspection proves the oil pump serviceable, lubricate the rotor assembly and pump housing with clean engine oil and reassemble the pump.
See Figures 1 and 2
- Clean the oil pickup tube and replace the O-ring.
- Position the tube on the oil pump and hand-start the 2 bolts. Install the bolt retaining the pickup tube to the main bearing stud spacer hand tight.
- Tighten the pickup tube-to-oil pump bolts to 6-9 ft. lbs. (8-12 Nm). Tighten the pickup tube to main bearing stud spacer bolt to 15-22 ft. lbs. (20-30 Nm).
- Rotate the inner rotor of the oil pump to align with the flats on the crankshaft and install the oil pump flush with the cylinder block. Install the 4 retaining bolts and tighten to 6-9 ft. lbs. (8-12 Nm).
- Install a new oil filter. Install the timing chains.
- Install the oil pan, front cover and camshaft covers.
- Fill the crankcase with the proper type and quantity of engine oil. Connect the negative battery cable, start the engine and check for leaks.
See Figure 3
- Prime the oil pump by filling either the inlet or outlet ports with engine oil and rotating the pump shaft to distribute the oil within the pump body.
- Position the intermediate driveshaft into the distributor socket. With the shaft firmly seated in the distributor socket, the stop on the shaft should touch the roof of the crankcase. Remove the shaft and position the stop, as necessary.
- Position a new gasket on the pump body, insert the intermediate shaft into the oil pump and install the pump and shaft as an assembly.
Do not attempt to force the pump into position if it will not seat readily. The driveshaft hex may be misaligned with the distributor shaft. To align, rotate the intermediate shaft into a new position.
- Tighten the oil pump attaching bolts to 22-32 ft. lbs. (30-43 Nm).
- Clean and install the oil pump inlet tube and screen assembly.
- Install the oil pan and the remaining components in the reverse order of removal. Start the engine and check for leaks.
See Figure 4