GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 43655 Camshaft Support Holding Tool
    • SA9127E Gauge Bar Set

Removal Procedure


    Object Number: 898897  Size: SH
  1. Disconnect the negative battery cable.
  2. Disconnect the intake air temperature (IAT) sensor connector.
  3. Loosen the clamp at the air cleaner assembly.
  4. Remove the push pin attachment from the outlet resonator/duct assembly to the support bracket.
  5. Loosen the clamp at the throttle body assembly.
  6. Disconnect the PCV fresh air vent hose at the cam cover.
  7. Remove the outlet resonator/duct assembly.

  8. Object Number: 951506  Size: SH
  9. Remove the ignition module assembly with the bolts.
  10. Disconnect the coolant de-gas hose clips from the fuel rail.

  11. Object Number: 895199  Size: SH
  12. Disconnect the ground strap at the rear of the cam cover assembly.

  13. Object Number: 854376  Size: SH
  14. Relieve the fuel system pressure. Refer to Fuel Pressure Relief .
  15. Disconnect the SA9127E after pressure has been relieved.

  16. Object Number: 854304  Size: SH
  17. Disconnect the fuel rail bracket and the bolt at the rear of the cam cover.

  18. Object Number: 854303  Size: SH

    Caution: Whenever fuel line fittings are loosened or disconnected, wrap a shop cloth around the fitting to collect fuel. Place the cloth in an approved container.

    Notice: An open-end wrench must be used to support the fuel line to rail connection during loosening/tightening to avoid damaging the fuel rail assembly.

  19. While supporting the fuel rail assembly with an open-end wrench, loosen the transfer line fitting at the fuel rail.

  20. Object Number: 897589  Size: SH
  21. Position the fuel line away from the cam cover assembly.

  22. Object Number: 894940  Size: SH
  23. Remove the cam cover assembly bolts.
  24. Remove the cam cover assembly.

  25. Object Number: 947496  Size: SH
  26. If intake camshaft is being removed, Remove the purge solenoid from the power steering plate.
  27. Remove the power steering block off the plate.
  28. Notice: To avoid valve piston contact, No. 1 cylinder piston must be positioned at approximately 60 degrees before-top dead center (BTDC). Pistons are properly positioned when the diamond shaped hole on the intake camshaft sprocket is located at 12 o'clock.

    Important: To rotate the camshaft(s), use a 24 mm open-end wrench on the camshaft flats. Camshaft(s) should be rotated in a clockwise direction only (facing camshaft sprockets from passenger side of the vehicle).

  29. Locate the No. 1 piston to approximately 60 degrees before top dead center (BTDC) (diamond shaped hole on the intake camshaft sprocket at 12 o'clock position).
  30. Remove the spark plugs. This will ease rotation effort.


    Object Number: 894944  Size: SH

    Important: When removing guide bolts do not drop down into front cover.

  31. Remove the upper timing chain guide.
  32. Notice: During the camshaft removal procedure, the pistons are locked in position by the J43655 camshaft support holding tool. Do not rotate the engine crankshaft or tool damage and timing reset will be required. Camshafts can be rotated only after the #1 piston is at 60° BTDC and the sprocket has been disengaged from the camshaft.

  33. Remove front camshaft caps.

  34. Object Number: 952042  Size: SH

    Important: Lubricate the sprocket pins with clean motor oil. These will allow sprockets to easily slide on the sprocket pins.

  35. Install J 43655 through the sprocket holes from the timing chain side of the sprocket towards the rear of the engine.

  36. Object Number: 896641  Size: SH
  37. With the guide pin installed in the sprocket, align the guide pins into the slots on the support plate.
  38. Tighten the support bracket to the cylinder head.
  39. Tighten
    Tighten the support plate to cylinder head to 10 N·m (89 lb in).

  40. Install wingnuts and tighten.

  41. Object Number: 896709  Size: SH
  42. Hold each camshaft in place using 24 mm open-end wrench and carefully remove the camshaft sprocket timing chain retaining bolts and washers. Discard the torque-to-yield (TTY) bolts.
  43. Important: When sliding the timing chain and the sprockets onto the guide pins, be sure the timing chain is positioned properly on the adjustable and fixed guide or guide damage will occur. Care should be taken when removing the camshaft sprocket from the camshaft.

    Important: Camshafts are spring loaded and may rotate. Care should be taken until all spring tension is removed from the camshaft.

  44. Slide camshaft sprockets away from the camshafts.

  45. Object Number: 876853  Size: SH
  46. To release the spring tension on the camshaft, after the camshaft is disengaged from the sprocket, rotate the camshaft using a 24 mm wrench to a neutral position.
  47. Uniformly loosen and remove the remaining camshaft bearing cap bolts.

  48. Object Number: 896721  Size: SH
  49. Carefully pull the camshafts straight up to avoid damaging the cylinder head thrust surfaces.
  50. Important: When servicing the cylinder head components. Components should be kept in order to assure proper assembly.


    Object Number: 895216  Size: SH
  51. Remove rocker arms followers.

  52. Object Number: 895281  Size: SH

    Notice: After cylinder block, head, or lifter replacement, it will be necessary to allow the engine to idle for 3-5 minutes. If the lifters are noisy, warm the engine up at less than 200 RPM. After the coolant temperature has reached approximately 85°C (185°F), cycle the engine RPM from idle to 300 RPM for approximately 10 minutes or drive the vehicle 8 kilometers (5 miles) to purge the air. If the air cannot be purged, the faulty lifters will have to be replaced.

    Important: During camshaft removal procedure, the pistons are locked by the J 43655 and SHOULD NOT be rotated. Tool damage may result and timing chain re-timing will be required.

  53. Remove the lash adjusters.

Installation Procedure


    Object Number: 895281  Size: SH

    Notice: If a valve seal is removed after it has been installed, it must be discarded. The valve stem lock groove will cut the seal's lip during removal. Use extreme care when installing valve retainers and do not damage the valve stems.

  1. Install lubricated lash adjusters in their correct locations.

  2. Object Number: 895216  Size: SH
  3. Install rocker arms followers.

  4. Object Number: 876853  Size: SH
  5. Lubricate camshaft bearing journals with clean engine oil and install both camshafts.
  6. When installing camshafts, attempt to position the camshaft slot in line with the notch on the sprockets.
  7. Notice: Refer to Fastener Notice in the Preface section.

  8. Install all bearing caps except for front cap and rear intake camshaft cap, if serviced. Tighten down the bearing cap uniformly.
  9. Tighten
    Tighten the camshaft bearing cap bolts to 10 N·m (89 lb in).


    Object Number: 894997  Size: SH

    Notice: Verify the timing chain is properly positioned on the fixed guide or guide damage will occur.

    Important: Ensure that the alignment slots are correctly aligned with notches in the camshaft sprockets before the final torque is applied.

    Important: Verify the camshafts are properly timed as outlined in this section prior to starting the engine.

  10. Slide the camshaft sprocket(s) and timing chain on guide pins toward the camshafts. Rotate camshafts with 24 mm open-end wrench to properly align the camshafts and sprockets.

  11. Object Number: 897666  Size: SH
  12. Install a new camshaft sprocket bolts and tighten. This will pull the camshaft sprockets and camshafts together.
  13. Hold the camshaft with 24 mm open-end wrench during the tightening.

    Tighten
    Tighten the camshaft sprocket bolts to 85 N·m(63 lb ft) + 30 degrees.


    Object Number: 952057  Size: SH
  14. Remove J 43655 .
  15. Install the front camshaft caps.
  16. Tighten
    Tighten the camshaft bearing cap bolts to 10 N·m (89 lb in).


    Object Number: 894944  Size: SH

    Important: Apply Permatex® Medium Blue P/N 21485277 to upper timing chain guide bolts.

  17. Install upper timing chain guide and bolts.
  18. Tighten
    Tighten the timing chain guide bolts to 10 N·m(89 lb in).


    Object Number: 895000  Size: SH

    Important: Apply Permatex® Flange Sealant 5131 Purple to cylinder head near the rear intake cap as shown.

  19. Install the rear intake camshaft bearing cap.
  20. Tighten
    Tighten the intake camshaft rear cap to 25 N·m (18 lb ft).


    Object Number: 951437  Size: SH
  21. Install power steering block off plate.
  22. Tighten
    Tighten the Power Steering Block Off Plate to 25 N·m (18 lb ft).


    Object Number: 894940  Size: SH
  23. Visually inspect the camshaft cover gasket for signs of leakage. The camshaft cover gasket is reusable if not damaged.
  24. Assemble camshaft cover and gasket. Use care to make sure that the gasket is located in the retaining groove on the camshaft cover.
  25. Install the cover on the cylinder head and hand-tighten the bolts.
  26. Tighten
    Tighten the camshaft cover bolts to 10 N·m (89 lb in).


    Object Number: 854303  Size: SH

    Notice: An open-end wrench must be used to support the fuel line to rail connection during loosening/tightening to avoid damaging the fuel rail assembly.

  27. Re-position the fuel line assembly.
  28. Install the transfer line fitting at the fuel-to-fuel rail.
  29. Tighten
    Tighten the transfer line fitting-to-fuel rail to 10 N·m (89 lb in).


    Object Number: 854304  Size: SH
  30. Connect the fuel rail bracket and the bolt to the cylinder head.
  31. Tighten
    Tighten the fuel line bracket bolt to 10 N·m (89 lb in).


    Object Number: 895199  Size: SH
  32. Connect the ground strap to the camshaft cover assembly.
  33. Tighten
    Tighten the camshaft cover ground strap bolts to 10 N·m (89 lb in).

  34. Connect the degas hose and clamp to the cylinder head.
  35. Connect the degas hose bracket and the bolt to the cylinder head.

  36. Object Number: 895073  Size: SH
  37. Install the spark plugs.
  38. Tighten

        • Tighten the spark plugs to 20 N·m(15 lb in).
        • Tighten the coolant pipe bracket bolts to 10 N·m (89 lb in).

    Object Number: 894939  Size: SH
  39. Install ignition module assembly to the cam cover and hand tighten the retaining bolts.
  40. Tighten
    Tighten ignition module-to-camshaft cover to 8 N·m (71 lb in).


    Object Number: 898897  Size: SH
  41. Position the outlet resonator/duct assembly into position.
  42. Connect PCV fresh air vent hose assembly.
  43. Tighten the clamp at the throttle body assembly.
  44. Position the outlet resonator/duct assembly up with support bracket and install the push-pin.
  45. Tighten the clamp at the air cleaner assembly.
  46. Connect the intake air temperature (IAT) sensor connector.
  47. Connect the negative battery cable.
  48. Tighten
    Tighten the battery terminal bolt to 17 N·m (13 lb ft).