Oil Pump: Service and Repair

Fig. 10 Oil Pump Removal:

Fig. 11 Oil Pump Assembly:

REMOVAL
1. Drain crankcase, then remove oil pan.
2. Remove pump to rear main bearing attaching bolt, then remove pump, Fig. 10.

DISASSEMBLY
1. Drain oil from pump, then remove driveshaft and driveshaft extension.
2. Remove pickup tube and screen.
3. Remove four pump cover to body attaching bolts, then remove cover, idler and drive gears, Fig. 11. Place alignment mark on oil pump drive and idler gear teeth so they can be installed in same position.
4. Remove pressure regulator valve retaining pin, spring and valve from pump body.

Fig. 12 Oil Pump Gear Lash Measurement:

Fig. 13 Oil Pump Housing Pocket Measurement:

INSPECTION
1. Inspect pump components and should any of following conditions exist, oil pump assembly should be replaced.
a. Inspect pump body, gears and cover for cracks or excessive wear.
b. Check drive gear shaft for looseness in housing.
c. Check inside of pump cover for wear that would allow oil to leak past ends of gears.
d. Check oil pickup screen assembly for damage to screen or pickup tube.
e. Check pressure regulator valve for fit in pump body.
2. Install pump gears, then using a feeler gauge, measure oil pump gear lash at several locations, Fig. 12. Clearance should be 0.0037-0.0077 inch on 3.1L engines.
3. Remove pump gears, then measure depth of oil pump housing pocket, Fig. 13. Depth should be 1.195-1.198 inch on engines with aluminum pump bodies, and 1.202-1.205 on engines with cast iron pump bodies.
4. Measure pump gear length. Length should be 1.199-1.2 inch.
5. Measure pump gear diameters. Diameters should be 1.498-1.5 inch on engines with aluminum pump bodies, and 1.504-1.506 on engines with cast iron pump bodies.
6. Install pump gears, then measure side clearance between pump gears and oil pump housing. Side clearance should be 0.003-0.004 inch.
7. If oil pump components are not within specifications, it should be replaced.

ASSEMBLY
Lubricate internal parts with engine oil during assembly.

1. Install replacement pickup screen and tube assembly, if removed. Position pump in a soft jawed vise, then apply sealer to end of tube and tap into position using suction tube installer tube tool No. J-8369, or equivalent, and a plastic hammer. Use care not to damage inlet screen and tube assembly when installing into pump housing.
2. Place pressure regulator valve, spring and retaining pin into pump body, then install drive gear and shaft.
3. Install idler gear into pump body, then pump cover gasket. Fig. 11.
4. Install pump cover, tighten retaining bolts to specifications.

INSTALLATION
1. Align oil pump extension shaft drive gear socket and pump housing, then install pump assembly. Tighten pump assembly retaining bolts to specifications.
2. Install oil pan as previously described.