SERVICE MANUAL UPDATE -2.5L CAMSHAFT GEAR REPLACEMENT
VEHICLES AFFECTED: 1990 CHEVROLET LUMINA WITH 2.5L
A revised service procedure has been developed for replacement of camshaft timing gears. The revised method does not require the complete removal of the engine from the vehicle. Cam gear replacement is generally accomplished by partially lowering the engine/frame assembly to gain access to the cam gear.
IMPORTANT! SEE APPROPRIATE SERVICE MANUAL SECTION FOR FASTENER TORQUE SPECIFICATIONS.
Tools Required:
J36462 Engine Support Adapter Leg J34995 Front Cover Oil Seal Installer J28467-A Engine Support Fixture J25033-B Cam Gear Installation Tool J24420-B Cam Gear Removal Tool J8001 Universal Dial Indicator W/Magnetic Base
Remove or Disconnect
1. Battery negative cable.
2. Coolant reservoir.
3. Air cleaner assembly.
4. Drain coolant.
5. Torque strut.
6. Install J28467-A and J36462.
7. Convenience center heat shield.
8. Serpentine belt.
9. Power steering pump and bracket.
10. Raise vehicle.
11. Both front tire and wheel assemblies.
12. Steering shaft pinch bolt.
13. Right front lower ball joint.
14. Right front brake line to body bracket.
15. Right front engine splash shield.
16. Drain engine oil.
17. Flywheel access covers.
18. Crankshaft pulley and bolt.
19. Frame bolts and insulators.
20. Lower vehicle.
21. Front cover bolts.
22. Lower frame/powertrain assembly about 4 inches using J28467-A and J36462.
23. Raise vehicle.
24. Front cover.
25. Front cover oil seal.
Clean
- Front cover and front cover mating surfaces.
26. Align crankshaft/camshaft timing marks on gears.
IMPORTANT! COVER OIL PAN OPENING WITH RAGS TO PREVENT CHIPS FROM FALLING INTO PAN.
CAUTION:
WEAR SAFETY GLASSES TO AVOID EYE DAMAGE.
IMPORTANT! USE CARE WHEN DRILLING AND TAPING CAM GEAR TO AVOID DAMAGE TO THE CAMSHAFT.
27. Drill hole on the camshaft centerline (8mm drill, 1/2 in. deep).
28. Tap the 8mm hole with a 3/8-16-NC bottoming tap.
IMPORTANT! AVOID BUILD-UP OF CHIPS. BACK OUT THE TAP EVERY FEW TURNS AND REMOVE CHIPS.
NOTICE: USE CARE TO AVOID DRILL WANDER THAT COULD DAMAGE CAMSHAFT.
29. Centre punch and drill (2) 3mm pilot holes in the metal hub of the cam gear (180 degrees apart).
30. Enlarge pilot holes with 5.5mm drill, 1/4 in. deep.
31. Tap 5.5mm holes with 1/4-28-NF bottoming tap.
32. Drill a hole no larger than 1mm (.040 in.) in the front oil gallery plug. This provides improved lubrication to the timing gears.
Clean
- Oil pan of debris
33. Cam gear using J24420-B, do not move camshaft or crankshaft.
Inspect
- Thrust plate for scuffing and or grooving. If evident, install new thrust plate, spacer ring, and key. Thrust plate to block bolts torque - 10 N.m (90 in. lbs.).
- Lubricate front thrust plate surface with clean engine oil.
Install or Connect
1. Cam gear using J25033-B, align timing marks.
Measure
- Camshaft end play using J8001. Push cam gear onto camshaft until camshaft end play is in the range of .0015 in. (.04 mm to .013 mm).
2. Front cover oil seal using J34995, lubricate seal lip with clean engine oil.
3. Apply RTV sealant to front cover sealing surfaces.
4. Front cover and bolts.
5. Brake line bracket to body bracket.
6. Crank pulley and bolt.
7. Flywheel access covers.
8. Right front splash shield.
9. Lower vehicle.
10. Raise frame/powertrain assembly using J28467-A and J34995.
11. Raise vehicle.
12. Frame bolts and insulators.
13. Lower ball joint and nut.
14. Steering shaft pinch bolt.
15. Both front tire and wheel assemblies.
16. Remove J28467-A and J36462.
17. Power steering pump bracket and pump.
18. Serpentine belt.
19. Convenience centre heat shield.
20. Air cleaner assembly.
21. Torque strut.
22. Coolant reservoir.
23. Add engine oil.
24. Add coolant.
25. Negative battery cable.
Inspect
- Front toe and adjust if necessary.
- For oil and coolant leaks with engine running at operating temperature.
- For proper completion of repairs.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
