GM Grand Am/Achieva/Calais/Skylark/Somerset 1985-98

Exhaust Manifold

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REMOVAL & INSTALLATION



2.0L Engine

See Figures 1 and 2

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the turbo induction tube.
  4.  



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Fig. Fig. 1: Removing the turbo induction tube is simply a matter of unfastening the clamps, then pulling the tube from the engine

  1. Label and detach the spark plug wires.
  2.  
  3. Remove the turbocharger. For details, please refer to the procedure located later in this section.
  4.  
  5. If applicable, detach the wiring from the oxygen sensor.
  6.  
  7. Unfasten the bolts and nuts retaining the exhaust manifold to the block and exhaust pipe, then remove the manifold. Remove and discard the gasket.
  8.  

To install:
  1. Install the exhaust manifold with a new gasket. Install the retainers, then tighten (in the sequence shown in the accompanying figure) the studs to 20 ft. lbs. (27 Nm,) and the nuts to 16 ft. lbs. (22 Nm).
  2.  

Tighten the No. 2 and 3 manifold runners prior to the No. 1 and 4 runners.



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Fig. Fig. 2: Exhaust manifold mounting and retainer tightening sequence

  1. Connect the exhaust pipe to the exhaust manifold and tighten the nuts to 19 ft. lbs. (25 Nm).
  2.  
  3. Attach the wire to the oxygen sensor, if applicable.
  4.  
  5. Install the turbocharger. For details, please refer to the procedure located later in this section.
  6.  
  7. Connect the spark plug wires as tagged during removal.
  8.  
  9. Install the turbo induction tube.
  10.  
  11. Connect the negative battery cable.
  12.  
  13. Start the engine and check for leaks.
  14.  

2.3L and 2.4L Engines

See Figures 3 and 4

  1. Disconnect the negative battery cable
  2.  
  3. Detach the oxygen sensor connector.
  4.  
  5. If accessible at this time, remove upper and lower exhaust manifold heat shields. Some vehicles only have one shield accessible when the vehicle is raised.
  6.  

For vehicles through 1989, it is necessary to relieve the spring pressure from one nut/bolt prior to removing the second nut/bolt. If the spring pressure is not relieved it will cause the exhaust pipe to twist and bind up the bolt as it is removed.

  1. For 1988-89 vehicles:
    1. Unfasten the nut/bolt that attaches the exhaust manifold brace to the manifold.
    2.  
    3. Break loose the manifold-to-exhaust pipe spring loaded nuts/bolts using a 13mm box wrench.
    4.  
    5. Raise and safely support the vehicle.
    6.  

  2.  
  3. For 1988-89 models, remove the manifold-to-exhaust pipe nuts/bolts from the exhaust pipe flange as follows:
    1. Unscrew either nut/bolt clockwise 4 turns.
    2.  
    3. Move to the other nut/bolt and turn it all the way out of the exhaust pipe flange.
    4.  
    5. Return to the first nut/bolt and rotate it the rest of the way out of the exhaust pipe flange.
    6.  

  4.  
  5. For 1990-98 vehicles:
    1. Raise and safely support the vehicle.
    2.  
    3. Unfasten the exhaust manifold brace-to-manifold bolt.
    4.  
    5. If not already done, remove the upper heat shield.
    6.  
    7. On the 2.4L engines, remove the exhaust manifold flex decoupler nuts.
    8.  
    9. Remove the manifold-to-exhaust pipe spring loaded nuts.
    10.  

  6.  

Do not bend the exhaust flex decoupler more than 3° in any direction. Movement of more than 3° will damage the flex decoupler.

  1. Pull down and back on the exhaust pipe to disengage it from the exhaust manifold bolts.
  2.  
  3. Carefully lower the vehicle.
  4.  
  5. Unfasten the exhaust manifold-to-cylinder head retaining nuts/bolts, then remove the manifold. Remove and discard the gasket.
  6.  
  7. Installation is the reverse of the removal procedure. If installing a new manifold, transfer the oxygen sensor from the old manifold to the new one. Coat the threads of the sensor with a suitable anti-seize compound prior to installation. Make sure to use a new gasket, then tighten the retainers, in sequence, to the following specifications:

    2.3L engine-1988-89 Exhaust manifold-to-cylinder head nuts-27 ft. lbs. (37 Nm)
     
    2.3L engine-1990-95 Exhaust manifold-to-cylinder head nuts-31 ft. lbs. (42 Nm)
     
    2.3L engine-Exhaust manifold-to-cylinder head studs-106 inch lbs. (12 Nm)
     
    2.4L engine-Exhaust manifold-to-cylinder head nuts-110 inch lbs. (13 Nm)
     
    2.4L engine-Heat shield bolts-124 inch lbs. (14 Nm)
     
    2.4L engine-Exhaust manifold brace-to-bolt-41 ft. lbs. (56 Nm)
     
    2.4L engine-Exhaust manifold brace-to-nut-19 ft. lbs. (26 Nm)
     
    2.4L engine-manifold flex decoupler-26 ft. lbs. (35 Nm)
     

  8.  



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Fig. Fig. 3: Exhaust manifold mounting and tightening sequence-2.3L engine



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Fig. Fig. 4: Exhaust manifold mounting and tightening sequence-2.4L engine

  1. Install the exhaust pipe flange bolts evenly and gradually to avoid binding.
  2.  
  3. Connect the negative battery cable, start the engine and check for leaks.
  4.  

2.5L Engine

See Figure 5

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner assembly and the hot air tube (if equipped).
  4.  



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Fig. Fig. 5: View of the exhaust manifold with bolt tightening sequence-2.5L engine

  1. Remove the alternator. For details, please refer to the procedure located in this section.
  2.  
  3. Detach the oxygen sensor connector.
  4.  
  5. Remove the oil level indicator tube.
  6.  
  7. Raise and safely support the vehicle.
  8.  
  9. Disconnect the exhaust pipe from the manifold.
  10.  
  11. Carefully lower the vehicle.
  12.  
  13. Bend the locking tabs away from the mounting bolts, the unfasten the exhaust manifold retaining bolts and washers and remove the exhaust manifold. Remove and discard the gasket.
  14.  
  15. Clean all gasket mating surfaces on the cylinder head and manifold.
  16.  
  17. Installation is the reverse of removal. Make sure to use a new gasket. Tighten using a crisscross pattern to the figures shown in the illustration.
  18.  
  19. Start the engine and check for leaks.
  20.  

3.0L Engine
LEFT (FRONT)

See Figure 6

  1. Disconnect the negative battery cable.
  2.  
  3. Tag and disconnect the spark plug wires.
  4.  
  5. Remove the manifold-to-crossover retaining bolts.
  6.  
  7. Unfasten the air cleaner assembly mounting bolts, then remove the assembly.
  8.  
  9. Remove the engine cooling fan.
  10.  
  11. Unfasten the manifold-to-cylinder head bolts.
  12.  
  13. Remove the oil level indicator tube and indicator.
  14.  



Click image to see an enlarged view

Fig. Fig. 6: View of the left (front) exhaust manifold mounting-3.0L engine

  1. Remove the exhaust manifold from the engine, then clean the mating surfaces using a suitable solvent.
  2.  
  3. Installation is the reverse of the removal procedure. Tighten the manifold-to-cylinder head bolts to 37 ft. lbs. (50 Nm). Tighten the crossover-to-manifold bolts to 15 ft. lbs. (20 Nm).
  4.  
  5. Connect the negative battery cable.
  6.  
  7. Start the engine and check for leaks.
  8.  

RIGHT (REAR)

See Figure 7

  1. Disconnect the negative battery cable.
  2.  
  3. Raise and safely support the vehicle.
  4.  
  5. Remove the two bolts attaching the exhaust pipe to the manifold.
  6.  
  7. Carefully lower the vehicle.
  8.  
  9. Detach the oxygen sensor electrical connector.
  10.  
  11. Tag and disconnect the spark plug wires.
  12.  
  13. Remove the two nuts retaining the crossover pipe to the manifold.
  14.  
  15. Remove the serpentine drive belt.
  16.  
  17. Unfasten the power steering pump retaining bolts, then remove the pump.
  18.  
  19. Disconnect the heater hose from the tube.
  20.  
  21. Remove the exhaust manifold heat shield.
  22.  
  23. Remove the C3I bracket nuts.
  24.  
  25. Unfasten the six bolts attaching the exhaust manifold, then remove the manifold from the engine.
  26.  



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Fig. Fig. 7: View of the rear (right) exhaust manifold mounting-3.0L engine

  1. Using a suitable solvent, clean the exhaust manifold mating surfaces.
  2.  

If installing a new exhaust manifold, transfer the oxygen sensor and exhaust pipe seal (if applicable) from the old manifold to the new one.

  1. Installation is the reverse of removal. Tighten the exhaust manifold bolts to 37 ft. lbs. (50 Nm).
  2.  
  3. Connect the negative battery cable.
  4.  
  5. Start the engine and check for leaks.
  6.  

3.1L Engine

See Figure 8

FRONT (LEFT)
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the top half of the air cleaner assembly and throttle cable duct.
  4.  
  5. Partially drain the cooling system.
  6.  
  7. Disconnect the radiator hose from the thermostat housing.
  8.  
  9. Detach the coolant bypass hose at the coolant pump and from the exhaust manifold.
  10.  
  11. Remove the exhaust crossover heat shield.
  12.  
  13. Detach the exhaust crossover pipe from the manifold.
  14.  
  15. Tag and disconnect the ignition wires from the spark plugs.
  16.  
  17. Remove the exhaust manifold heat shield.
  18.  
  19. Unfasten the exhaust manifold retaining nuts, then lift the manifold and gasket from the engine.
  20.  
  21. Clean mating surfaces at the cylinder head and manifold.
  22.  

To install:
  1. Install the exhaust manifold gasket and the exhaust manifold. Tighten the manifold mounting nuts to 12 ft. lbs (16 Nm).
  2.  
  3. Install the exhaust manifold heat shield and tighten the bolts to 89 inch lbs. (10 Nm).
  4.  
  5. Connect the exhaust crossover pipe to the manifold.
  6.  
  7. Install the exhaust crossover pipe heat shield.
  8.  
  9. Attach the ignition wires to the appropriate spark plugs.
  10.  
  11. Connect the coolant by-pass pipe to the coolant pump and exhaust manifold.
  12.  
  13. Attach the radiator hose to the coolant outlet housing.
  14.  
  15. Install the top half of the air cleaner and the throttle body duct.
  16.  
  17. Connect the negative battery cable.
  18.  
  19. Start the engine and check for leaks.
  20.  



Click image to see an enlarged view

Fig. Fig. 8: Left and right side exhaust manifold mounting-3.1L engine

REAR (RIGHT)
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the top half of the air cleaner assembly and throttle cable duct.
  4.  
  5. Remove the exhaust crossover heat shield.
  6.  
  7. Detach the exhaust crossover pipe from the manifold.
  8.  
  9. Remove the heated oxygen sensor.
  10.  
  11. Disconnect the EGR pipe from the exhaust manifold.
  12.  
  13. Raise and safely support the front of the vehicle.
  14.  
  15. Remove the transaxle oil fill tube and lever indicator assembly.
  16.  
  17. Disconnect the front exhaust pipe from the exhaust manifold.
  18.  
  19. Disconnect the exhaust pipe from the converter flange, then support the converter.
  20.  
  21. Remove the converter heat shield from the body.
  22.  
  23. Remove the exhaust manifold heat shield.
  24.  
  25. Unfasten the exhaust manifold nuts, then remove the manifold and gasket from the bottom of vehicle.
  26.  
  27. Clean mating surfaces at the cylinder head and manifold.
  28.  

To install:
  1. Position the exhaust manifold gasket, then install the manifold loosely and install heat shield at this time.
  2.  
  3. Install the manifold nuts and tighten to 12 ft. lbs (16 Nm).
  4.  
  5. Install the exhaust manifold heat shield nuts and tighten them to 12 ft. lbs. (16 Nm).
  6.  
  7. Install the converter heat shield to the body.
  8.  
  9. Attach the exhaust pipe to the converter flange.
  10.  
  11. Connect the exhaust pipe to the exhaust manifold.
  12.  
  13. Install the transaxle oil level indicator and fill tube assembly.
  14.  
  15. Carefully lower the vehicle.
  16.  
  17. Install the heated oxygen sensor.
  18.  
  19. Attach the cross-over pipe to the exhaust manifolds and the cross-over heat shield.
  20.  
  21. Connect the EGR pipe to exhaust manifold.
  22.  
  23. Install the top half of the air cleaner assembly and the throttle body duct.
  24.  
  25. Connect the negative battery cable.
  26.  
  27. Start the engine and check for leaks.
  28.  

3.3L Engine
FRONT (LEFT)

See Figures 9 and 10

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner inlet ducting
  4.  
  5. Tag and disconnect the spark plug wires.
  6.  
  7. Unfasten the exhaust crossover pipe to manifold bolts.
  8.  



Click image to see an enlarged view

Fig. Fig. 9: View of the exhaust crossover pipe removal-3.3L engine

  1. Remove the engine lift hook and manifold heat shield.
  2.  
  3. Remove the oil level indicator tube and the indicator.
  4.  
  5. Unfasten the exhaust manifold studs, then remove the manifold.
  6.  



Click image to see an enlarged view

Fig. Fig. 10: View of the left exhaust manifold mounting-3.3L engine

  1. Installation is the reverse of the removal procedure. Tighten the nuts to 19 ft. lbs. (26 Nm) and the studs to 30 ft. lbs. (41 Nm).
  2.  

REAR (RIGHT)

See Figures 9 and 11

  1. Disconnect the negative battery cable.
  2.  
  3. Tag and disconnect the spark plug wires.
  4.  
  5. Detach the oxygen sensor electrical connection.
  6.  
  7. Remove the throttle cable bracket, then unfasten the cables from the throttle body.
  8.  
  9. Detach the brake booster hose from the manifold.
  10.  
  11. Unfasten the two exhaust crossover pipe-to-manifold bolts.
  12.  
  13. Remove the exhaust pipe-to-manifold bolts.
  14.  
  15. Remove the engine lift hook.
  16.  
  17. Remove the transaxle oil level indicator tube.
  18.  
  19. Remove the manifold heat shield.
  20.  
  21. Unfasten the manifold studs and bolt, then remove the manifold.
  22.  



Click image to see an enlarged view

Fig. Fig. 11: View of the right exhaust manifold mounting-3.3L engine

  1. Installation is the reverse of the removal procedure. Tighten the nuts to 19 ft. lbs. (26 Nm) and the studs to 30 ft. lbs. (41 Nm).
  2.  

 
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