Oil Pump: Service and Repair

This article has been updated with TSB 91-6-17.

OIL PUMP COVER

IMPORTANT
^ It is not necessary to remove the balancer assembly to service the oil pump or pressure regulator valve. Refer to Balance Shaft. Service and Repair

TOOL REQUIRED:
^ J 28467-A Engine Support Fixture

Figure 1 - Force Balancer Assembly and Oil Pump Cover Components:

REMOVE OR DISCONNECT
1. Negative battery cable.
2. Air cleaner and duct assembly.
3. Serpentine belt.
4. Engine torque strut from engine bracket.
5. Two upper front A/C compressor bolts to upper mounting bracket.
6. Install J 28467-A
7. Raise vehicle and suitably support.
8. Right front tire and wheel assembly.
9. Right side engine splash shield.
10. Exhaust pipe and converter.
11. Lower front A/C compressor mounting bolt and support bracket.
12. Rear A/C compressor mounting bracket bolts.
13. Wire harness from bell housing bracket.
14. Flywheel cover retaining bolts.
15. Starter and support bracket, set aside.
16. Flywheel over.
17. Engine support bracket bolts from engine.
18. Loosen transaxle mounting nuts.
19. Lower vehicle.
20. Raise front of engine about 3 inches, using J 28467-A.
21. Engine support bracket nuts from engine mount and frame assembly. Remove support bracket and mount.
22. Raise vehicle and suitably support.
23. Drain engine oil.
24. Using a jack stand, place a wood support along transaxle oil pan inside edge, raise transaxle and engine assembly to normal sitting position with J 28467-A in position.
25. Oil Pan retaining bolts.
26. Oil pan from engine block.

CLEAN
^ Engine block and oil pan surface.

27. Oil filter.
28. Oil pump cover assembly.
29. Oil pump gears.

CAUTION: THE PRESSURE REGULATOR VALVE SPRING IS UNDER PRESSURE. EXERCISE CAUTION WHEN REMOVING THE PIN, AS BODILY INJURY MAY RESULT.

30. Pressure regulator valve
-Plug or pin Spring
-Valve. If valve is stuck, clean the valve and pump.
-Housing with carburetor cleaning solvent.

CAUTION: AVOID BREATHING THE FUMES, OR EXPOSURE OF THE SKIN TO THE CLEANING SOLVENT, AS BODILY INJURY MAY RESULT. WHEN WORKING OVERHEAD, WEAR EYE PROTECTION.

CLEAN
^ All parts of sludge, oil and varnish. Varnish on parts may be removed by soaking in carburetor or cleaning solvent.

INSPECT
For foreign material and determine source.
Pump housing and oil pump cover assembly for:
- Cracks
- Scoring
- Casting imperfections
Pressure regulator valve for:
- Scoring
- Sticking. Burrs may be removed with a fine oil stone.
Pressure regulator valve spring for:
- Loss of tension
- Bending
- If in doubt, replace the spring
Screen assembly for:
- Looseness
- Broken wire mesh or screen
Gerotor oil pump for:
- Chipping
- Galling
- Wear
Measure
- Gerotor housing pocket depth
- Gerotor thickness

IMPORTANT:
When deciding pump serviceability based on pocket depth, consider depth of wear pattern in gear pocket and face oil pump cover assembly.

INSTALL OR CONNECT
1. Pack pump with petroleum jelly. Lubricate all internal parts with clean engine oil.

NOTICE: TO AVOID ENGINE DAMAGE, ALL PUMP CAVITIES MUST BE PACKED WITH PETROLEUM JELLY BEFORE INSTALLING THE GEARS TO ASSURE PRIMING.

2. Pressure regulator valve and spring.
3. Plug or pin.
^ Make sure pin is properly secured.
4. Oil pump gears.
5. Oil pump cover assembly.

TIGHTEN
^ Bolts to 10 Nm (89 lbs.in.).

6. Oil filter.
7. Apply RTV sealer GM P/N 12345739 or equivalent.
8. Oil pan to engine block.
9. Oil pan retaining bolts.

TIGHTEN
^ Bolts to 10 Nm (89 lbs.in.).

10. Remove jack stand and wood support.
11. Lower vehicle.
12. Fill engine oil.

NOTICE: IF THE OIL PRESSURE DOES NOT BUILD UP ALMOST IMMEDIATELY, REMOVE THE OIL PAN AND EXAMINE PUMP. IF NECESSARY, DISASSEMBLE THE OIL PUMP AND REPACK ALL CAVITIES WITH PETROLEUM JELLY. RUNNING THE ENGINE WITHOUT MEASURABLE OIL PRESSURE WILL CAUSE EXTENSIVE DAMAGE.

INSPECT
^ Remove the oil pressure sending unit and install an oil pressure gage. Start engine and observe oil pressure. Check for bearing knock. If necessary, disassemble and check for adequate oil supply and proper clearance.

13. Engine support bracket and nuts to engine mount.

TIGHTEN
^ Nuts to 47 Nm (35 lbs.ft.).

14. Engine mount and nuts to frame assembly.

TIGHTEN
^ Nuts to 47 Nm (35 lbs.ft.).

15. Lower front of engine.
16. Raise vehicle.
17. Transaxle mounting nuts.

TIGHTEN
^ Nuts to 50 Nm (37 lbs.ft.).

18. Engine support bracket bolts to engine.

TIGHTEN
^ Bolts to 50 Nm (37 lbs.ft.).

19. Flywheel cover.
20. Starter assembly and support bracket.
21. Flywheel cover attaching bolts.

TIGHTEN
^ Bolts to 10 Nm (89 lbs.in.).

22. Wire harness at bell housing bracket.
23. Rear A/C compressor mounting bracket bolts.

TIGHTEN
^ Bolts to 25 Nm (18 lbs.ft.).

24. Lower front A/C compressor mounting bolts and support brace.
25. Exhaust pipe and converter.
26. Right side engine splash shield.
27. Right front tire and wheel assembly.
28. Lower vehicle.
29. Remove J 28467-A.
30. Upper front A/C compressor to mounting bracket bolts.

TIGHTEN
^ Bolts to 25 Nm (18 lbs.ft.).

31. Engine torque strut to engine bracket.
32. Serpentine belt.
33. Air cleaner and duct assembly.
34. Negative battery cable.

INSPECT
^ Oil level