S&T Series Blazer, Bravada, Envoy, Jimmy, Rainier, Trailblazer, Xtreme

Exhaust Manifold

Print

Removal & Installation



4.2L Engine
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove or disconnect the following:
    NOTE
    It will be easier if the vehicle is only supported to a height where underhood access is still possible, the vehicle may be left in position for the entire procedure. If the vehicle is raised too high for underhood access, it will have to lowered, raised and lowered again during the procedure.



    Negative battery cable
     



    Air cleaner resonator outlet duct
     
    Transmission filler tube stud nut from the Air Injector Reactor (AIR) adapter and move the tube aside
     
    Oil level indicator tube
     
    Oxygen (O 2 ) sensor from the exhaust manifold
     
    4 manifold heat shield nuts and shield
     
    Exhaust pipe bolts from the exhaust manifold
     
    Exhaust manifold bolts, and manifold
     
    Old gaskets and discard
     

  4.  

To install:

  1. Using a putty knife, clean the gasket mounting surfaces. Inspect the exhaust manifold for distortion, cracks or damage; replace if necessary.
  2.  
  3. Apply a threadlock such as GM 12345493 to the threads of the manifold retainers prior to installation.
  4.  
  5. Install or connect the following:
    NOTE
    Apply a suitable anti-seize compound to the exhaust manifold heat shield nuts prior to installation.



    Exhaust manifold to the cylinder using a new gasket, then tighten the bolts, in 3 passes, in sequence, to 18 ft. lbs. (25 Nm)

    Click image to see an enlarged view

    Fig. Exhaust manifold bolt tightening sequence-4.2L engine

     
    Heat shield studs, if necessary, and tighten to 89 inch lbs. (10 Nm)
     
    O 2 sensor
     
    Exhaust manifold heat shield
     



    Heat shield nuts and tighten to 44 inch lbs. (5 Nm)
     
    Exhaust pipe to the manifold with seal and retaining nuts. Tighten the nuts to 37 ft. lbs. (50 Nm).
     
    Oil level indicator tube
     
    Transmission filler tube back onto the AIR adapter block stud and secure with the nut. Tighten the bracket nut to 89 inch lbs. (10 Nm).
     
    Air cleaner resonator outlet duct
     
    Negative battery cable.
     

  6.  

4.3L Engine
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove or disconnect the following:
    NOTE
    It will be easier if the vehicle is only supported to a height where underhood access is still possible, the vehicle may be left in position for the entire procedure. If the vehicle is raised too high for underhood access, it will have to lowered, raised and lowered again during the procedure.



    Negative battery cable
     



    Exhaust pipe from the exhaust manifold. It may be necessary to remove the tires to gain access to the rear manifold bolts.
     
    Engine oil dipstick tube bolt, if removing the right side manifold on 2001 models
     
    Exhaust Gas Recirculation (EGR) inlet pipe from the left side manifold, if necessary.
     
    Engine Coolant Temperature (ECT) sensor electrical connection, on 2001 models
     
    Upper radiator support hose and nut, on 2001 models
     
    Steering intermediate shaft, if removing the left side manifold on 2001 models
     
    Wheel house extension, if removing the right side manifold on 2001 models
     
    Spark plugs wires from the plugs
     
    Nuts attaching the secondary air injection pipe to the manifold, on 2001 models
     
    Air injection pipe and gasket, on 2001 models
     
    Locktangs (unbend), the exhaust manifold retaining bolts, washers and tab washers
     
    Heat shields
     
    Exhaust manifold
     
    Old gaskets and discard
     

  4.  

To install:

  1. Using a putty knife, clean the gasket mounting surfaces. Inspect the exhaust manifold for distortion, cracks or damage; replace if necessary.
  2.  
  3. On 2001 models, apply a threadlock such as GM 12345493 to the threads of the manifold retainers prior to installation.
  4.  
  5. Install or connect the following:

    Exhaust manifold to the cylinder using a new gasket, then tighten the center bolts to 11 ft. lbs. (15 Nm) and the front and rear manifold bolts to 22 ft. lbs. (30 Nm). Once the bolts are tightened, bend the tabs on the washers back over the heads of all bolts in order to lock them in position.
     
    Spark plug wires to the plugs
     
    Fender wheelhouse extension and the tire assembly, if removed on 2001 models
     
    Secondary air injection pipe with a NEW gasket to the manifold and tighten the nuts to 18 ft. lbs. (25 Nm), if removed on 2001 models
     
    EGR inlet pipe, if removed
     
    ECT sensor electrical connection, if removed
     
    Upper radiator hose support and nut, if removed
     
    Steering intermediate shaft, if removed on 2001 models (left side manifold only)
     
    Engine oil dipstick tube bolt to 106 inch lbs. (12 Nm), if removed
     
    Exhaust pipe to the manifold
     
    Negative battery cable
     

  6.  

5.3L Engine
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable
     
    Spark plug wires from the spark plugs. Don-t disconnect the wires from the ignition coil unless necessary for clearance.
     
    Exhaust manifold bolts, manifold and gasket. Discard the gasket.
     
    Heat shield bolt and shield, if necessary
     

  4.  

To install:

  1. Apply a 0.2 inch (5mm) bead of threadlock GM P/N 12345493, or equivalent to the threads of the exhaust manifold bolts. Do NOT apply sealer to the first 3 threads of the bolts.
  2.  
  3. Install or connect the following:

    New exhaust manifold gasket
     
    Exhaust manifold
     
    Exhaust manifold bolts. Tighten in two passes. First to 11 ft. lbs. (15 Nm), then to 18 ft. lbs. (25 Nm) for 2003-04 models or 15 ft. lbs. (20 Nm) for 2005 models, starting with the center bolts and working outward.
     

  4.  
  5. Bend over the exposed edge of the gasket at the rear of the cylinder head using a flat punch or equivalent tool.

    Heat shield and bolts, if removed. Torque the bolts to 80 inch lbs. (9 Nm).
     
    Spark plug wires to the spark plugs
     
    Negative battery cable
     

  6.  

 
label.common.footer.alt.autozoneLogo