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

Intake Manifold

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REMOVAL & INSTALLATION



2.0L Engine

See Figure 1

  1. Disconnect the negative battery cable, then properly drain the cooling system and relieve the fuel system pressure.
  2.  
  3. Disconnect the induction tube and hoses.
  4.  
  5. Tag and detach the wiring to the throttle body, MAP sensor and the wastegate.
  6.  
  7. Disconnect the PCV hose.
  8.  
  9. Tag and disconnect the vacuum hoses from the throttle body.
  10.  
  11. Disconnect the throttle cable and, if equipped, the cruise control cable.
  12.  
  13. Disconnect the fuel return line from the throttle cable support bracket.
  14.  
  15. Tag and disconnect the wiring from the ignition coil, then remove the coil bracket.
  16.  
  17. Tag and detach the vacuum lines from the rear of the manifold.
  18.  
  19. Remove the transaxle fill tube and manifold support brackets.
  20.  
  21. Remove the heater tube support bracket from the lower side of the manifold.
  22.  
  23. Disconnect the fuel injector wiring.
  24.  
  25. Remove the coolant recovery tank.
  26.  
  27. Remove the accessory drive belt, then remove the alternator.
  28.  
  29. Remove the power steering adjusting bracket and the alternator front adjusting bracket.
  30.  
  31. Disconnect the power steering pump bracket from the cylinder head and engine block.
  32.  
  33. Disengage the fuel rail-to-fuel inlet fitting.
  34.  
  35. Detach the fuel return line from the regulator outlet.
  36.  
  37. Unfasten the intake manifold retaining nuts and washers, then remove the manifold from the engine.
  38.  

If installing a new intake manifold, transfer all necessary parts from the old manifold to the new one.

  1. Using a suitable scraping tool, clean the old gasket material from the intake manifold mating surfaces. Do NOT let any debris fall into the engine!
  2.  



Click image to see an enlarged view

Fig. Fig. 1: View of the intake manifold

To install:
  1. Position a new gasket on the manifold, then install the manifold. Install the retaining washers and nuts, then tighten them to 18 ft. lbs. (25 Nm) starting from the middle and working outward.
  2.  
  3. Connect the fuel return line to the regulator outlet, then engage the fuel line to the fuel rail inlet.
  4.  
  5. Install the power steering pump bracket to the cylinder head and block.
  6.  
  7. Fasten the alternator front adjusting bracket and the power steering adjusting bracket.
  8.  
  9. Install the alternator, then secure the accessory drive belt.
  10.  
  11. Position and install the coolant recovery tank.
  12.  
  13. Connect the wiring to the fuel injectors.
  14.  
  15. Install the heater tube support bracket on the lower side of the manifold.
  16.  
  17. Install the manifold support and the transaxle fill tube brackets.
  18.  
  19. Attach the vacuum hoses to the rear of the manifold.
  20.  
  21. Install the ignition coil bracket, then connect the wires as tagged during removal.
  22.  
  23. Connect the fuel return line to the throttle cable support bracket.
  24.  
  25. Attach the throttle cable and the cruise control cable (if equipped).
  26.  
  27. Connect the vacuum hoses to the throttle body as tagged during removal.
  28.  
  29. Install the PCV hose.
  30.  
  31. Fasten the wiring to the wastegate, MAP sensor and the throttle body as tagged during removal.
  32.  
  33. Connect the induction tube and hoses.
  34.  
  35. Refill the cooling system to the proper level, then connect the negative battery cable. Start the engine and inspect for coolant leakage.
  36.  

2.3L Engine

See Figures 2 and 3

  1. Disconnect the negative battery cable, then properly drain the cooling system.
  2.  
  3. Detach the vacuum hose and electrical connector from the MAP sensor.
  4.  
  5. Disengage the electrical connectors from the MAT/IAT sensor and the purge solenoid.
  6.  
  7. Disconnect the fuel injector harness, then position it aside.
  8.  
  9. Label and disconnect the vacuum hoses from the intake manifold and the hose at the fuel regulator and purge solenoid to the canister.
  10.  
  11. Disconnect the throttle body and vent tube-to-air cleaner ducts.
  12.  
  13. Remove the throttle cable bracket.
  14.  
  15. Disconnect the power brake vacuum line (including the retaining bracket-to-power steering bracket) and position it aside.
  16.  
  17. Disconnect the coolant lines from the throttle body, then remove the throttle body.
  18.  
  19. Remove the oil air separator (crankcase ventilation system) as an assembly. Leave the hoses attached to the separator. Disconnect the hoses from the oil fill, chain cover, intake duct and the intake manifold.
  20.  
  21. Detach the oil/air separator from the oil fill tube.
  22.  
  23. Remove the oil fill cap and oil level indicator assembly.
  24.  
  25. Unfasten the oil fill tube bolt/screw, then pull the tube upward to remove.
  26.  
  27. Detach the injector harness connector.
  28.  
  29. Remove the fill tube out the top, rotating as necessary to gain clearance for the oil/air separator nipple between the intake tubes and fuel rail electrical harness.
  30.  
  31. Remove the intake manifold support brace.
  32.  
  33. Unfasten the manifold retaining nuts and bolts, then remove the intake manifold from the engine. Loosen in reverse of the torque sequence to prevent manifold warping.
  34.  

If installing a new intake manifold, transfer all necessary parts from the old manifold to the new one.

  1. Using a suitable scraping tool, clean the old gasket material from the intake manifold mating surfaces. Do NOT let any debris fall into the engine!
  2.  

To install:
  1. Install the manifold with a new gasket.
  2.  

Make sure that the numbers stamped on the gasket are facing towards the manifold surface.

  1. Follow the tightening sequence in the accompanying figure, then tighten the bolts/nuts to 19 ft. lbs. (26 Nm).
  2.  



Click image to see an enlarged view

Fig. Fig. 2: View of the mounting of the 2.3L engine intake manifold. When tightening the bolts, be sure to follow the proper tightening sequence

  1. Install the intake manifold brace and retainers.
  2.  



Click image to see an enlarged view

Fig. Fig. 3: Intake manifold brace mounting

  1. Lubricate a new oil fill tube O-ring seal with clean engine oil, then install the tube down between intake manifold. Rotate as needed to gain clearance for the oil/air separator nipple on the fill tube.
  2.  
  3. Position the oil fill tube in its cylinder block opening. Align the fill tube so it is in about its proper position. Place the palm of your hand over the oil fill opening and press straight down to seat the fill tube and O-ring into the cylinder block.
  4.  
  5. Connect the oil/air separator hose to the oil fill tube. You can lubricate the hose as necessary to ease installation. Install the oil fill tube bolt/screw.
  6.  
  7. Install the throttle body to the intake manifold using a new gasket, then connect the coolant lines to the throttle body.
  8.  
  9. Connect the power brake vacuum hose to the throttle body, then secure the pipe to the power steering bracket.
  10.  
  11. Install the throttle/accelerator control cable bracket.
  12.  
  13. Connect the vacuum hoses to the intake manifold and connect the fuel regulator hose.
  14.  
  15. Attach all electrical connectors, as tagged during removal.
  16.  
  17. Install the air cleaner duct.
  18.  
  19. Install the coolant recovery tank and refill the coolant to it's proper level.
  20.  
  21. Connect the negative battery cable, then start the engine and inspect for leaks.
  22.  

2.4L Engine

See Figures 4, 5, 6 and 7

Do not attempt to work on the engine while it is warm, you may become burned. Also do not attempt to install a cold manifold on a hot engine, parts damage could result.

  1. Disconnect the negative battery cable.
  2.  
  3. Tag and disconnect the following electrical wiring harnesses:

    MAP sensor
     
    Intake Air Temperature (IAT) sensor
     
    EVAP canister
     
    Fuel injection harness
     

  4.  
  5. Remove the vacuum hoses from the fuel regulator and EVAP canister purge solenoid to canister.
  6.  
  7. Remove the air cleaner duct.
  8.  
  9. Disconnect the accelerator control cable bracket.
  10.  
  11. Remove the stud ended alternator mount bolt.
  12.  



Click image to see an enlarged view

Fig. Fig. 4: Remove the stud located on the top of the alternator

  1. Disconnect the EGR pipe from the EGR adapter.
  2.  
  3. Raise and safely support the front of the vehicle securely on jackstands.
  4.  
  5. Loosen and remove the intake manifold support brace.
  6.  
  7. Lower the front end of the vehicle.
  8.  
  9. Remove the intake manifold retaining nuts and bolts. Loosen in reverse of the torque sequence to prevent manifold warping.
  10.  
  11. Carefully lift off the manifold and scrape all the old gasket material off the mating surface.
  12.  

To install:
  1. Position a new gasket and lay the intake manifold in place. Be sure when installing the gasket, that the numbers stamped on it are faced toward the manifold surface.
  2.  
  3. Tighten the manifold bolts in the correct tightening sequence to 18 ft. lbs. (24 Nm).
  4.  



Click image to see an enlarged view

Fig. Fig. 5: Attach the intake manifold and tighten in sequence all the retaining bolts

  1. Raise and support the front of the vehicle.
  2.  
  3. Attach the intake manifold brace. Start by finger tightening the bolts, then push the brace against the manifold and tighten bolts A then B to specifications.
  4.  



Click image to see an enlarged view

Fig. Fig. 6: View of the intake manifold brace

  1. Lower the front end of the vehicle and attach the EGR pipe to the adapter. Tighten the fasteners to 19 ft. lbs. (26 Nm).
  2.  



Click image to see an enlarged view

Fig. Fig. 7: Attach the EGR pipe and secure the bolts to specification

  1. Attach the stud ended alternator bolt.
  2.  
  3. Install the accelerator control cable bracket.
  4.  
  5. Attach the vacuum hoses to the fuel regulator and EVAP canister Purge solenoid.
  6.  
  7. Attach all electrical wiring that had been previously detached.
  8.  
  9. Install the air cleaner duct.
  10.  
  11. Connect the negative battery cable.
  12.  

2.5L Engine

See Figures 8 and 9

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner assembly and hot air pipe (if equipped).
  4.  
  5. Detach the PCV valve and hose at the TBI assembly.
  6.  
  7. Properly drain the cooling system.
  8.  
  9. Properly relieve the fuel system pressure as described in Fuel System , then disconnect the fuel lines.
  10.  
  11. Label and detach the vacuum hoses.
  12.  
  13. Tag and remove the wiring and throttle linkage from the TBI assembly.
  14.  
  15. Remove the transaxle downshift linkage.
  16.  
  17. If equipped, remove the cruise control linkage/servo cable.
  18.  
  19. For vehicles through 1987, remove the throttle linkage and bellcrank and lay aside for clearance.
  20.  
  21. For 1988-91 vehicles, disconnect the throttle and T.V. cable and position out of the way.
  22.  
  23. Disconnect the heater hose.
  24.  
  25. For 1986 vehicles, remove the alternator brace and ignition coil.
  26.  
  27. Remove the retaining bolts, then lift the intake manifold from the vehicle.
  28.  
  29. Using a suitable scraping tool, clean the old gasket material from the intake manifold mating surfaces. Do NOT let any debris fall into the engine!
  30.  

To install:
  1. Position the intake manifold, with a new gasket, on the engine. Install the retaining bolts, then tighten to the specifications shown in the accompanying figures.
  2.  



Click image to see an enlarged view

Fig. Fig. 8: Intake manifold mounting and bolt tightening specifications-1986 2.5L engine



Click image to see an enlarged view

Fig. Fig. 9: Intake manifold mounting and bolt tightening specifications-1987-91 2.5L engines

  1. If removed, install the ignition coil and the alternator brace.
  2.  
  3. Connect the heater hose.
  4.  
  5. For 1988-91 vehicles, connect the throttle and T.V. cable.
  6.  
  7. For vehicles through 1987, connect the throttle linkage and bellcrank.
  8.  
  9. If equipped, connect the cruise control linkage/servo cable.
  10.  
  11. Install the transaxle downshift linkage bracket.
  12.  
  13. Connect the wiring and throttle linkage to the TBI assembly.
  14.  
  15. Attach the vacuum hoses as tagged during removal.
  16.  
  17. Fasten the fuel lines.
  18.  
  19. Connect the PCV valve and hose at the throttle body.
  20.  
  21. Fill the cooling system, using the proper type and amount of coolant.
  22.  
  23. Install the air cleaner assembly.
  24.  
  25. Connect the negative battery cable, then start the engine and check for coolant and/or vacuum leaks.
  26.  

3.0L Engine

See Figures 10, 11, 12 and 13

For some vehicles, a special bolt wrench J-24394 or equivalent is required for this procedure.

  1. Properly relieve the fuel system pressure, then disconnect the fuel lines from the rail.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Disconnect the mass air flow sensor and air intake duct.
  6.  
  7. Remove the serpentine accessory drive belt, alternator and bracket.
  8.  
  9. Remove the C3I ignition module with the spark plug cables attached. Tag all wiring connectors before detaching from the spark plugs.
  10.  
  11. Label and disengage all vacuum lines and wiring connectors as necessary to gain clearance to remove the manifold.
  12.  
  13. Remove the throttle, cruise control (if equipped) and T.V. cables from the throttle body.
  14.  
  15. Properly drain the cooling system.
  16.  
  17. Disconnect the heater hoses from the throttle body.
  18.  
  19. Remove the upper radiator hose.
  20.  
  21. If not already done, disconnect the fuel lines, then remove the fuel rail and injectors.
  22.  
  23. Remove the intake manifold mounting bolts. Loosen in reverse of the torque sequence to prevent manifold warping. Remove the intake manifold from the engine.
  24.  



Click image to see an enlarged view

Fig. Fig. 10: Unfasten the manifold mounting bolts, then ...



Click image to see an enlarged view

Fig. Fig. 11: ... lift the intake manifold from the engine

  1. Using a suitable scraping tool, clean the old gasket material from the intake manifold mating surfaces. Do NOT let any debris fall into the engine!
  2.  



Click image to see an enlarged view

Fig. Fig. 12: Remove and discard the old manifold gasket

To install:
  1. Position a new manifold gasket, apply sealer No. 1050026 (or equivalent high tack sealer) if a steel gasket is used. Apply sealer 12345336 (or equivalent RTV sealant) to the ends of the manifold gasket.
  2.  
  3. Apply sealer 1052080 (or equivalent thread locking compound) to the manifold bolt threads, then install the bolts. Tighten the manifold bolts in the sequence in the accompanying figure to 32 ft. lbs. (44 Nm).
  4.  



Click image to see an enlarged view

Fig. Fig. 13: Be sure to tighten the manifold bolts in the correct sequence

  1. Install the injectors and fuel rail.
  2.  
  3. Install the upper radiator hose, then connect the heater hoses to the throttle body.
  4.  
  5. Connect the T.V., cruise control (if equipped), and throttle cables to the throttle body.
  6.  
  7. Attach all vacuum lines and wiring connectors as labeled during removal.
  8.  
  9. Install the ignition module, then connect the wires to the as tagged during removal.
  10.  
  11. Install the alternator, bracket and serpentine belt.
  12.  
  13. Install the air intake duct, then connect the mass airflow sensor.
  14.  
  15. Fill the cooling system with the proper type and quantity of coolant.
  16.  
  17. Connect the negative battery cable, then start the engine and check for coolant and/or vacuum leaks.
  18.  

3.1L Engine

See Figure 14

The 3.1L engine is equipped with upper and lower intake manifolds. The upper intake manifold is also known as the intake manifold plenum.


CAUTION
The fuel system is under pressure and must be properly relieved before disconnecting the fuel lines. Failure to properly relieve the fuel system pressure can lead to personal injury and component damage.

  1. Relieve the fuel system pressure.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove top half of the air cleaner assembly and throttle body duct.
  6.  
  7. Drain and recycle the engine coolant.
  8.  
  9. Disconnect the EGR pipe from exhaust manifold.
  10.  
  11. Remove the serpentine belt.
  12.  
  13. Remove the brake vacuum pipe at the intake plenum.
  14.  
  15. Disconnect the control cables from the throttle body and intake plenum mounting bracket.
  16.  
  17. Remove the power steering lines at the alternator bracket.
  18.  
  19. Remove the alternator.
  20.  
  21. Label and disconnect the ignition wires from the spark plugs and wire retainers on the intake plenum.
  22.  
  23. Remove the ignition assembly and the EVAP canister purge solenoid together.
  24.  



Click image to see an enlarged view

Fig. Fig. 14: View of the intake manifold and related components

  1. Disconnect the upper engine wiring harness connectors at the following components:

    Throttle Position Sensor (TPS)
     
    Idle Air Control (IAC)
     
    Fuel Injectors
     
    Coolant temperature sensor
     
    Manifold Absolute Pressure (MAP) sensor
     
    Camshaft Position (CMP) sensor
     

  2.  
  3. Tag and disconnect the vacuum lines from the following components:

    Vacuum modulator
     
    Fuel pressure regulator
     
    PCV valve
     

  4.  
  5. Disconnect the MAP sensor from upper intake manifold.
  6.  
  7. Remove the upper intake plenum mounting bolts and lift off the plenum.
  8.  
  9. Disconnect the fuel lines from the fuel rail and bracket.
  10.  
  11. Install engine support fixture special tool J 28467-A or an equivalent.
  12.  
  13. Remove the right side engine mount.
  14.  
  15. Remove the power steering mounting bolts and support the pump out of the way without disconnecting the power steering lines.
  16.  
  17. Disconnect the coolant inlet pipe from the outlet housing.
  18.  
  19. Remove the coolant bypass hose from the water pump and the cylinder head.
  20.  
  21. Disconnect the upper radiator hose at thermostat housing.
  22.  
  23. Remove the thermostat housing.
  24.  
  25. Remove both rocker arm covers.
  26.  
  27. Remove the lower intake manifold bolts. Make sure the washers on the four center bolts are installed in their original locations.
  28.  

When removing the valve train components they should be kept in order for installation the original locations.

  1. Remove the rocker arm retaining nuts or bolts and extract the rocker arms and pushrods.
  2.  
  3. Remove the intake manifold from the engine. Remove and discard the gasket.
  4.  
  5. Using a suitable scraper, clean gasket material from all mating surfaces. Remove all excess RTV sealant from front and rear ridges of cylinder block.
  6.  

To install:
  1. Place a 0.12 inch (3mm) bead of RTV, on each ridge, where the front and rear of the intake manifold contact the block.
  2.  
  3. Using a new gasket, place the intake manifold on the engine.
  4.  
  5. Install the pushrods in their original locations. Coat the pushrods with prelube.
  6.  

The intake pushrods are marked yellow (5 3 /4 inch long) and the exhaust are green (6 inches long). Make sure the pushrods are properly seated in the valve lifters and rocker arms.

  1. Position the rocker arms in there original locations and tighten to specifications. Refer to the procedure earlier in this section.
  2.  
  3. Install lower the intake manifold attaching bolts. Apply sealant 12345739 (or equivalent thread locking compound) to the threads of bolts. Tighten the vertical bolts first then the diagonal bolts to 115 inch lbs. (13 Nm).
  4.  
  5. Install the front rocker arm cover.
  6.  
  7. Install the thermostat housing.
  8.  
  9. Connect the upper radiator hose to the thermostat housing.
  10.  
  11. Fasten the coolant inlet pipe to thermostat housing.
  12.  
  13. Connect coolant bypass pipe at the water pump and cylinder head.
  14.  
  15. Install the power steering pump in the mounting bracket.
  16.  
  17. Loosely install the serpentine belt.
  18.  
  19. Connect the right side engine mount.
  20.  
  21. Remove the special engine support tool.
  22.  
  23. Fasten the fuel lines to fuel rail and bracket.
  24.  
  25. Install the upper intake manifold and tighten the mounting bolts to 18 ft. lbs. (25 Nm).
  26.  
  27. Install the MAP sensor.
  28.  
  29. Connect the upper engine wiring harness connectors to the related components removed earlier.
  30.  
  31. Connect the vacuum lines to the PCV, vacuum modulator and fuel pressure regulator.
  32.  
  33. Install the EVAP canister purge solenoid and ignition assembly.
  34.  
  35. Install the alternator assembly.
  36.  
  37. Connect the power steering line to the alternator bracket.
  38.  
  39. Install the serpentine belt.
  40.  
  41. Connect the spark plug wires to the spark plugs and intake plenum wire retainer.
  42.  
  43. Install the EGR pipe to the exhaust manifold.
  44.  
  45. Attach the control cables to the throttle body lever and upper intake plenum mounting bracket.
  46.  
  47. Install air intake assembly and top half of the air cleaner assembly.
  48.  
  49. Install the brake vacuum pipe.
  50.  
  51. Fill the cooling system.
  52.  
  53. Connect the negative battery cable, then start the vehicle and verify that there are no leaks.
  54.  

3.3L Engine

See Figures 15 and 16

  1. Properly relieve the fuel system pressure, then disconnect the fuel lines from the fuel rail.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Properly drain the coolant.
  6.  
  7. Disconnect the accessory drive belt.
  8.  
  9. Remove the alternator and the braces/supports.
  10.  
  11. Remove the power steering pump and braces/supports.
  12.  
  13. Disconnect the coolant bypass hose, the heater pipe and the upper radiator hose.
  14.  
  15. Remove the air inlet duct.
  16.  
  17. Remove the throttle cable bracket and unfasten the cables from the throttle body.
  18.  
  19. Label and detach the vacuum hoses from the intake manifold.
  20.  
  21. Tag and disengage any electrical connectors to access the manifold.
  22.  
  23. Remove the fuel rail.
  24.  
  25. Disconnect the vapor canister purge line.
  26.  
  27. Detach the heater hose from the throttle body.
  28.  
  29. Tag and disconnect the rear spark plug wires.
  30.  
  31. Remove the intake manifold mounting bolts, then remove the manifold from the engine. Remove and discard the gasket.
  32.  



Click image to see an enlarged view

Fig. Fig. 15: View of the intake manifold mounting-3.3L engine

  1. Using a suitable scraping tool, clean the old gasket material from the intake manifold mating surfaces. Do NOT let any debris fall into the engine! Clean the cylinder block, heads and intake manifold surfaces of all oil using a suitable solvent.
  2.  

To install:
  1. Apply RTV type sealer to the ends of a new manifold gasket then position the gasket.
  2.  
  3. Clean the intake manifold bolts and bolt holes of all adhesive compound.
  4.  
  5. Position the intake manifold over the new gasket. Apply a suitable thread locking compound to the intake manifold bolt threads, then install the bolts and tighten the bolts, in sequence, in two steps to 88 inch lbs. (10 Nm).
  6.  



Click image to see an enlarged view

Fig. Fig. 16: Be sure to tighten the bolts twice in this sequence-3.3L engine

  1. Attach the rear spark plugs wires tagged during removal.
  2.  
  3. Connect the heater hose to the throttle body.
  4.  
  5. Attach the vapor canister purge line.
  6.  
  7. Install the fuel rail.
  8.  
  9. Attach any electrical connectors or vacuum lines that were removed to access the manifold.
  10.  
  11. Fasten the cables to the throttle body, then install the throttle cable bracket.
  12.  
  13. Install the air inlet duct.
  14.  
  15. Connect the upper radiator hose, the heater pipe and the coolant bypass hose.
  16.  
  17. Install the power steering braces/supports and the pump
  18.  
  19. Install the alternator braces/support, then install the alternator.
  20.  
  21. Install the accessory drive belt.
  22.  
  23. Fill the coolant system with the correct type and quantity of coolant.
  24.  
  25. Connect the negative battery cable, then start the engines and check for coolant and/or vacuum leaks.
  26.  

 
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