GM Lumina/Grand Prix/Cutlass Supreme/Regal 1988-1996

Intake Manifold

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REMOVAL & INSTALLATION




CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or inPuddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

2.2L Engine

See Figures 1 and 2



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Fig. Fig. 1: Upper intake manifold (plenum) bolt tightening sequence-2.2L engine



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Fig. Fig. 2: Lower intake manifold bolt tightening sequence-2.2L engine

  1. Disconnect the negative battery cable.
  2.  
  3. Properly relieve the fuel system pressure, as outlined in Fuel System of this repair guide.
  4.  
  5. Remove the air cleaner assembly.
  6.  
  7. Properly drain the coolant into a suitable container.
  8.  
  9. Remove the serpentine drive belt.
  10.  
  11. Unbolt the power steering pump and set it aside. Do NOT disconnect the fluid lines.
  12.  
  13. Tag and detach any necessary vacuum lines or electrical connectors.
  14.  
  15. Remove the accelerator cable bracket.
  16.  
  17. Remove the MAP sensor and EGR solenoid valve.
  18.  
  19. Unfasten the retaining nuts, then remove the upper intake manifold.
  20.  
  21. Remove the EGR valve injector.
  22.  
  23. Remove the fuel injector retainer bracket, regulator and the injectors.
  24.  
  25. Unfasten the manifold retaining nuts, then remove the lower intake manifold. Remove and discard the gasket.
  26.  
  27. Thoroughly clean the gasket mating surfaces with a suitable gasket scraper.
  28.  

To install:
  1. Position a new gasket, then place the lower manifold over it. Install the retaining nuts and tighten to 22 ft. lbs. (30 Nm).
  2.  
  3. Install the fuel injector retainer bracket, regulator and the injectors. Tighten the bolt/screw to 31 inch lbs. (3.5 Nm).
  4.  
  5. Position the EGR valve injector so the port is facing directly towards the throttle body.
  6.  
  7. Install the upper intake manifold and secure with the retaining nuts. Tighten the nuts to 22 ft. lbs. (30 Nm).
  8.  
  9. Install the EGR solenoid valve and the MAP sensor and seal. Be sure the MAP sensor is installed properly. Tighten the sensor retaining bolt to 27 inch lbs. (3 Nm); do not overtighten.
  10.  
  11. Position the accelerator cable bracket and secure with the retaining bolts and nut. Tighten the bolts to 18 ft. lbs. (25 Nm) and the nut to 22 ft. lbs. (30 Nm).
  12.  
  13. Attach the vacuum lines and electrical connectors, as tagged during removal.
  14.  
  15. Position the power steering pump and secure with the retaining bolts.
  16.  
  17. Install the serpentine drive belt.
  18.  
  19. Install the air cleaner assembly, then connect the negative battery cable.
  20.  
  21. Refill the engine with the specified type and amount of engine coolant. Start the engine and check for coolant leaks.
  22.  

2.3L Engine

See Figure 3, 4, 5 and 6



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Fig. Fig. 3: Remove the vent tube-to-air cleaner duct



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Fig. Fig. 4: The intake manifold bolts must be tightened in sequence



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Fig. Fig. 5: Install the brace and tighten the retainers to specification



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Fig. Fig. 6: Position the throttle cable bracket and secure with the retainers

  1. Disconnect the negative battery cable. Properly drain the cooling system.
  2.  
  3. Properly relieve the fuel system pressure as outlined in Fuel System of this repair guide.
  4.  
  5. If necessary for access, remove the coolant recovery tank.
  6.  
  7. Disconnect the vacuum hose and the electrical connector from the MAP sensor.
  8.  
  9. Detach the electrical connectors from the MAP sensor, MAT sensor, Purge solenoid and the fuel injector harness and position the harness aside.
  10.  
  11. Tag and disconnect the vacuum hoses from the intake manifold and hose at the fuel regulator and purge solenoid to canister.
  12.  
  13. Disconnect the throttle body-to-air cleaner duct.
  14.  
  15. Remove the vent tube-to-air cleaner duct.
  16.  
  17. Remove the throttle cable bracket.
  18.  
  19. Remove the power brake vacuum hose, including the retaining bracket-to-power steering bracket, and position it aside.
  20.  
  21. Disconnect the coolant hoses from the throttle body, then remove the throttle body from the intake manifold.
  22.  
  23. Remove the oil/air separator (crankcase ventilation system). Leave the hoses attached to the separator, disconnect them from the oil fill, chain cover, intake duct and the intake manifold. Remove as an assembly.
  24.  
  25. Disconnect the oil/air separator from the oil fill tube.
  26.  
  27. Remove the oil fill cap and oil level indicator dipstick.
  28.  
  29. Unfasten the retaining bolts, then pull the oil tube fill upward to unseat from block and remove.
  30.  
  31. Detach the injector harness connector.
  32.  
  33. 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.
  34.  
  35. Unfasten the intake manifold support brace bolts and nut, then remove the brace.
  36.  
  37. Remove the intake manifold retaining nuts and bolts, then remove the intake manifold. The hole closest to the chain housing is slotted for additional clearance. Remove and discard the gasket.
  38.  
  39. Thoroughly clean the gasket mating surfaces with a suitable gasket scraper.
  40.  

To install:
  1. Thoroughly clean and dry the mating surfaces. Install new gaskets and place the intake manifold inPosition.
  2.  
  3. Tighten the intake manifold bolts/nuts, in sequence, to 18 ft. lbs. (25 Nm). Tighten intake manifold brace and retainers hand-tight. Tighten, in sequence, as follows:
    1. Nut to stud bolt: 18 ft. lbs. (25 Nm)
    2.  
    3. Bolt to intake manifold: 40 ft. lbs. (55 Nm)
    4.  
    5. Bolt to cylinder block: 40 ft. lbs. (55 Nm)
    6.  

  4.  
  5. Lubricate a new oil fill tube ring seal with engine oil and install tube between No. 1 and 2 intake tubes. Rotate as necessary to gain clearance for oil/air separator nipple on fill tube.
  6.  
  7. Locate the oil fill tube in its cylinder block opening. Align the fill tube so it is approximately in its installed position. Press straight down to seat fill tube and seal into cylinder block.
  8.  
  9. Lubricate the hoses and install the oil/air separator assembly.
  10.  
  11. Install the throttle body to intake manifold using a new gasket. Attach the coolant hoses.
  12.  
  13. Install the power brake vacuum hose and the retaining bracket to power steering bracket.
  14.  
  15. Install the throttle cable bracket.
  16.  

  1. Attach the throttle body-to-air cleaner duct.
  2.  
  3. Connect the vacuum hoses to the intake manifold and the hose at the fuel regulator and the purge solenoid to the canister.
  4.  
  5. Attach the electrical connectors to the MAP sensor, MAT sensor, Purge Solenoid and the fuel injector harness.
  6.  
  7. Connect the vacuum line to the MAP sensor.
  8.  
  9. If removed, install the coolant recovery tank.
  10.  
  11. Fill all fluids to their proper levels.
  12.  
  13. Connect the negative battery cable, then start the engine and check for leaks.
  14.  

2.5L Engine

See Figure 7



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Fig. Fig. 7: Intake manifold bolt tightening sequence-2.5L engine

  1. Relieve the fuel system pressure as outlined in Fuel System .
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the air cleaner assembly.
  6.  
  7. Detach the MAP sensor connector.
  8.  
  9. Properly drain the cooling system into a suitable container.
  10.  
  11. Rotate the engine forward, as outlined earlier in this information.
  12.  
  13. Remove the PCV valve and hose from the throttle body assembly and valve cover.
  14.  
  15. Remove the fuel lines from the throttle body and position them aside.
  16.  
  17. Tag and disconnect the vacuum lines and brake booster hose from the throttle body.
  18.  
  19. Detach all electrical connectors and control cables from the TBI assembly.
  20.  
  21. Unfasten the control cable bracket bolts, then position the bracket aside.
  22.  
  23. Unfasten the heater hose clamps, then detach the hose from the intake manifold.
  24.  
  25. Remove the power steering pump bolts then position it aside. Do NOT disconnect the pump fluid lines.
  26.  
  27. Unfasten the intake manifold retaining bolts, then remove the manifold. Remove and discard the gasket.
  28.  

To install:
  1. Clean all gasket surfaces on the cylinder head and intake manifold.
  2.  
  3. Position the intake manifold with a new gasket on the engine.
  4.  
  5. Install all the retaining bolts and washers hand-tight. Tighten the bolts, inProper sequence, to 25 ft. lbs. (34 Nm).
  6.  
  7. Install power steering pump assembly. Tighten the bolts to 20 ft. lbs. (27 Nm).
  8.  
  9. Attach the heater hose to the intake manifold and secure with the retaining clamp.
  10.  
  11. Install the control cable and retaining bolts. Tighten the bolts to 20 ft. lbs. (27 Nm).
  12.  
  13. Attach the control cables and electrical connectors to the throttle body.
  14.  
  15. Connect the vacuum hoses, including the power brake booster hose.
  16.  
  17. Attach the fuel lines.
  18.  
  19. Fasten the PCV valve and hose to the throttle body and valve cover.
  20.  
  21. Rotate the engine back into its original position and install the torque strut.
  22.  
  23. Refill the engine cooling system to the proper level with the correct type of coolant.
  24.  
  25. Install the air cleaner assembly and MAP sensor connector.
  26.  
  27. Connect the negative battery cable, then start the engine and check for fluid leaks.
  28.  

2.8L and 3.1L Engine

1988-90 VEHICLES



See Figures 8 and 9

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Fig. Fig. 8: Disconnect, then plug the fuel lines



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Fig. Fig. 9: Intake manifold mounting-1988 2.8L engine shown

  1. Disconnect the negative battery cable.
  2.  
  3. Drain the cooling system into a suitable container.
  4.  
  5. Properly relieve the fuel system pressure as outlined in Fuel System .
  6.  
  7. Disconnect the TV and accelerator cables from the plenum.
  8.  
  9. Unfasten the throttle body-to-plenum bolts, then remove the throttle body. Remove the EGR valve.
  10.  
  11. Remove the plenum-to-intake manifold bolts, then remove the plenum.
  12.  
  13. Disconnect and plug the fuel lines and return pipes from the fuel rail.
  14.  
  15. Remove the serpentine drive belt cover and belt.
  16.  
  17. Unfasten the power steering pump-to-bracket bolts and support the pump out of the way. Do NOT disconnect the pressure hoses.
  18.  
  19. Remove the alternator-to-bracket bolts and support the alternator out of the way. Remove the alternator bracket.
  20.  
  21. From the throttle body, disconnect the idle air vacuum hose.
  22.  
  23. Label and detach the electrical connectors from the fuel injectors. Remove the fuel rail.
  24.  
  25. Remove the breather tube. Disconnect the runners.
  26.  
  27. Unfasten the rocker arm cover-to-cylinder head bolts and remove both covers.
  28.  
  29. Disconnect the radiator hose from the thermostat housing.
  30.  
  31. Tag and detach the electrical connectors from the coolant temperature sensor and oil pressure sending unit. Remove the coolant sensor.
  32.  
  33. Disconnect the heater inlet pipe from the manifold.
  34.  
  35. Unfasten the intake manifold-to-cylinder head bolts, then remove the manifold. Remove and discard the gasket.
  36.  
  37. Loosen the rocker arm nuts, turn them 90º and remove the pushrods; be sure to keep the components in order for installation purposes.
  38.  
  39. Thoroughly clean all of the gasket mounting surfaces.
  40.  

To install:
  1. Place a bead of RTV sealer or equivalent on each ridge where the intake manifold and block meet. Install the intake manifold gasket in place on the block.
  2.  
  3. Install the pushrods and reposition the rocker arms. Make sure the pushrods seat properly in the lifter. Tighten the rocker arm nuts to 18 ft. lbs. (25 Nm).
  4.  
  5. Mount the intake manifold on the engine, using a new gasket, then tighten the bolts to 23 ft. lbs. 32 (Nm).
  6.  
  7. Connect the heater inlet pipe to the manifold.
  8.  
  9. Install and connect the coolant sensor. Attach the wire at the oil sending switch.
  10.  
  11. Connect the radiator hose at the thermostat outlet.
  12.  
  13. Install the rocker arm (valve) covers and tighten the retaining bolts to 90 inch lbs. (10 Nm)
  14.  
  15. Install the runners, breather tube, fuel rail and connect the wires at the fuel injectors.
  16.  
  17. Attach the idle air vacuum hose to the throttle body.
  18.  
  19. Install the alternator bracket and the alternator. Install the power steering pump.
  20.  
  21. Install the serpentine belt and belt cover.
  22.  
  23. Connect the fuel lines to the fuel rail.
  24.  
  25. Install the plenum,
  26.  
  27. Attach the EGR valve to the plenum.
  28.  
  29. Mount the throttle body to the plenum.
  30.  
  31. Connect the accelerator cable and the TV cable to the plenum.
  32.  
  33. Fill the cooling system. Connect the negative battery cable.
  34.  
  35. Run the engine until it reaches normal operating temperature and check for coolant and oil leaks.
  36.  

1991-93 VEHICLES

See Figures 10, 11, 12, 13, 14, 15, 16, 17 and 18

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Fig. Fig. 10: Use the correct size socket to unfasten the intake plenum retaining bolts



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Fig. Fig. 11: Remove the retaining bolts...



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Fig. Fig. 12: ... then remove the intake plenum from the vehicle



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Fig. Fig. 13: Remove the plenum gaskets and thoroughly clean the mating surfaces



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Fig. Fig. 14: Disconnect the fuel feed and return lines from the fuel rail



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Fig. Fig. 15: Unfasten the bolts, then remove the power steering pump and position aside. DO NOT disconnect the fluid lines



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Fig. Fig. 16: Unfasten the intake manifold retaining bolts...



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Fig. Fig. 17: ... then remove the intake manifold from the vehicle



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Fig. Fig. 18: Intake manifold bolt tightening sequence - 1991-93 3.1L engine

  1. Remove the air cleaner assembly.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Properly relieve the fuel system pressure as outlined in Fuel System .
  6.  
  7. If equipped, unfasten the engine strut mounts at the engine strut mount bracket, then pull the strut up and out of the way.
  8.  
  9. Drain the cooling system into a suitable container.
  10.  
  11. Remove the throttle body from the plenum.
  12.  
  13. Remove the EGR valve from the plenum.
  14.  
  15. If equipped, disconnect the brake booster pipe at the plenum.
  16.  
  17. Remove the plenum-to-intake manifold bolts and the plenum. Remove the plenum gaskets.
  18.  
  19. Unfasten the fuel line bracket bolt, then remove the bracket.
  20.  
  21. Disconnect the fuel lines from the fuel rail.
  22.  
  23. Rotate the engine forward, as outlined earlier in this information.
  24.  
  25. Remove the alternator bolts and support the alternator out of the way.
  26.  
  27. Remove the power steering line clamp nut at the alternator bracket.
  28.  
  29. Unfasten the alternator mounting bracket bolts, then remove the bracket.
  30.  
  31. Remove the front engine lift bracket studs, then remove the lift bracket.
  32.  
  33. Unfasten the power steering pump mounting bolts and support the pump out of the way. Do NOT disconnect the pressure hoses.
  34.  
  35. Disconnect the power brake booster pipe bracket at the rear cylinder head.
  36.  
  37. Unfasten the rear alternator pencil brace bolt, then remove the brace.
  38.  
  39. Tag and disconnect the spark plug wires from the rear cylinder head. Remove the rear valve cover, as outlined earlier in this information.
  40.  
  41. Rotate the engine back to its original position.
  42.  
  43. Unfasten the upper radiator hose clamp, then disconnect the hose from the engine.
  44.  
  45. Remove the coolant bypass pipe retaining bolts and the bracket nut. Remove the bypass pipe and gasket.
  46.  
  47. Remove the front valve cover, as outlined earlier in this information.
  48.  
  49. Detach the electrical connections from the intake manifold and fuel injectors.
  50.  
  51. Remove the coolant sensor.
  52.  
  53. Remove the heater inlet pipe assembly from the cylinder head and intake manifold.
  54.  
  55. Remove the bypass hose from the filler neck and cylinder head. Remove top radiator hose.
  56.  
  57. Unfasten the intake manifold-to-cylinder head bolts, then remove the manifold. If necessary, tag and detach any necessary vacuum lines. Remove and discard the gasket.
  58.  
  59. Loosen the rocker arm nuts, turn them 90º and remove the pushrods; be sure to keep the components in order for installation purposes.
  60.  
  61. Clean all of the gasket mounting surfaces.
  62.  

To install:
  1. Place a bead of RTV sealer or equivalent on each ridge where the intake manifold and block meet. Install the intake manifold gasket in place on the block.
  2.  
  3. Install the pushrods and reposition the rocker arms. Tighten the rocker arm nuts to 18 ft. lbs. (25 Nm).
  4.  
  5. Mount the intake manifold on the engine, using a new gasket, then tighten the bolts, in two steps, as follows:
    1. 1st step: tighten in sequence to 15 ft. lbs. (20 Nm).
    2.  
    3. 2nd step: tighten in sequence to 23 ft. lbs. (29 Nm).
    4.  

  6.  
  7. Connect any necessary vacuum lines, as tagged during removal.
  8.  
  9. Connect the heater inlet pipe to the cylinder head and intake manifold. Install and connect the coolant sensor.
  10.  
  11. Attach the electrical connectors at the intake manifold and fuel injectors.
  12.  
  13. Install the front valve cover, using a new gasket and bolts grommets. Tighten the bolts to 89 inch lbs. (10 Nm).
  14.  
  15. Install the coolant bypass pipe and gasket. Secure the coolant bypass pipe retaining bolts and bracket nut.
  16.  
  17. Connect the upper radiator hose to the engine and secure with the retaining clamp.
  18.  
  19. Rotate the engine assembly forward, as outlined earlier in this information.
  20.  
  21. Install the rear valve cover, using a new gasket and bolts grommets. Tighten the bolts to 89 inch lbs. (10 Nm).
  22.  
  23. Connect the spark plug wires to the rear plugs, as tagged during removal.
  24.  
  25. Install the rear alternator pencil brace and secure with the retaining bolt.
  26.  
  27. Attach the power brake booster pipe bracket at the rear of the cylinder head.
  28.  
  29. Place the power steering pump in its original position and install the retaining bolts.
  30.  
  31. Install the front engine lift bracket and studs. Tighten the studs to 40 ft. lbs. (55 Nm).
  32.  
  33. Install the alternator bracket and secure with the retaining bolts. Tighten the bolts to 37 ft. lbs. (50 Nm).
  34.  
  35. Fasten the power steering line clamp nut at the alternator bracket.
  36.  
  37. Install the alternator and secure with the retaining bolts.
  38.  
  39. Rotate the engine back to its original position.
  40.  
  41. Connect the fuel lines to the fuel rail. Install the fuel line bracket and retaining bolt.
  42.  
  43. Install the intake plenum. Tighten the retaining bolts to 88 inch lbs. (10 Nm). If equipped, connect the brake booster pipe at the plenum.
  44.  
  45. Attach the EGR valve to the plenum.
  46.  
  47. Install the throttle body, as outlined in Fuel System of this repair guide.
  48.  
  49. Install the engine strut mounts at the engine strut mount bracket. Tighten the nuts to 41 ft. lbs. (56 Nm).
  50.  
  51. Fill the cooling system. Connect the negative battery cable.
  52.  
  53. Run the engine until it reaches normal operating temperature and check for coolant and oil leaks.
  54.  

1994-96 VEHICLES

See Figures 19 and 20

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Fig. Fig. 19: Unfasten the retainers, then remove the upper manifold



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Fig. Fig. 20: Lower intake manifold removal-1995 3.1L engine shown

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner and duct assembly.
  4.  
  5. Properly relieve the fuel system pressure as outlined in Fuel System .
  6.  
  7. Drain the cooling system into a suitable container.
  8.  
  9. Remove the coolant recovery reservoir.
  10.  
  11. Remove the serpentine drive belt.
  12.  
  13. Disconnect the accelerator control and cruise control servo cables from the throttle body.
  14.  
  15. Remove the accelerator control cable bracket and move the cable assemblies aside.
  16.  
  17. Unfasten the thermostat bypass pipe clip nut from the upper intake manifold.
  18.  
  19. Remove the automatic transaxle vacuum modulator pipe assembly.
  20.  
  21. Disconnect the power brake booster vacuum hose from the manifold.
  22.  
  23. Unfasten the engine mount strut assemblies from the engine.
  24.  
  25. Rotate the engine assembly, as outlined earlier in this information.
  26.  
  27. Detach the electrical connectors from the ignition coil assembly, then remove the ignition coil.
  28.  
  29. Remove the alternator front and rear braces.
  30.  
  31. Tag and detach the electrical connectors from the manifold assembly.
  32.  
  33. Disconnect any necessary vacuum hoses.
  34.  
  35. Remove the MAP sensor and the EGR valve assembly.
  36.  
  37. Unfasten the retaining bolts and screws, then remove the upper intake manifold (plenum) assembly. Remove and discard the gaskets.
  38.  
  39. Disconnect the fuel feed and return lines from the lower manifold assembly.
  40.  
  41. Remove the fuel rail.
  42.  
  43. Remove the power steering pump pulley, then unfasten the power steering bolts. Position the pump aside but do NOT disconnect the fluid lines.
  44.  
  45. Disconnect the heater inlet pipe from the manifold.
  46.  
  47. Detach the upper radiator hose from the engine.
  48.  
  49. Remove the tie straps from the heater outlet pipe and the ignition wiring harness assembly.
  50.  
  51. Disconnect the heater pipe from the heater core-to-water pump assembly.
  52.  
  53. Remove the rocker arm (valve) covers. Remove and discard the gaskets.
  54.  
  55. Unfasten the lower manifold retaining screws, then remove the manifold from the vehicle.
  56.  

To install:
  1. Thoroughly clean all gasket mating surfaces.
  2.  
  3. Apply a 0.08-0.11 in. (8-12mm) bead of RTV sealer on the each ridge where the front and rear of the manifold assembly contact the engine block.
  4.  
  5. Position the manifold on the block using a new gasket. Hand-tighten the vertical, then the diagonal retaining bolts/screws after applying suitable sealer to the threads. Tighten the vertical, then the diagonal bolts/screws to 115 inch lbs. (5 Nm).
  6.  
  7. Install the rocker arm (valve) covers, as outlined earlier in this information.
  8.  
  9. Attach the heater pipe to the heater core-to-water pump assembly.
  10.  
  11. Fasten the tie straps around the heater outlet pipe and ignition wiring harness assembly.
  12.  
  13. Connect the upper radiator hose to the engine.
  14.  
  15. Position the power steering pump and secure with the retainers.
  16.  
  17. Install the power steering pump pulley.
  18.  
  19. Install the fuel rail assembly. Connect the fuel feed and return pipes to the fuel rail.
  20.  
  21. Position the upper manifold assembly, using new gaskets. Secure with the studs and bolts/screws. Tighten the bolts/screws to 18 ft. lbs. (25 Nm).
  22.  
  23. Install the EGR valve and the MAP sensor.
  24.  
  25. Connect any necessary vacuum hoses and electrical connectors to the manifold assembly.
  26.  
  27. Install the alternator front and rear braces.
  28.  
  29. Install the ignition coil and attach the electrical connector.
  30.  
  31. Rotate the engine assembly back to its original position.
  32.  
  33. Install the engine mount strut assemblies to the engine.
  34.  
  35. Connect the power brake booster vacuum hose to the manifold.
  36.  
  37. Install the automatic transaxle vacuum module pipe assembly.
  38.  
  39. Fasten the thermostat bypass clip nut to the upper intake manifold assembly.
  40.  
  41. Install the accelerator control cable bracket and the accelerator control and cruise control cable servo assemblies to the throttle body.
  42.  
  43. Install the serpentine drive belt and the coolant recovery reservoir.
  44.  
  45. Install the air cleaner assembly.
  46.  
  47. Fill the cooling system. Connect the negative battery cable.
  48.  
  49. Run the engine until it reaches normal operating temperature and check for coolant and oil leaks.
  50.  

3.4L Engine

See Figures 21 and 22



Click image to see an enlarged view

Fig. Fig. 21: Unfasten the retaining bolts, then remove the upper intake manifold (plenum)



Click image to see an enlarged view

Fig. Fig. 22: Lower intake manifold removal-1995 3.1L engine shown

Much of this procedure involves servicing the intake plenum. Do not confuse it with the intake manifold. They are separate entities and are separately serviceable, although the intake plenum must first be removed to gain access to the fuel rail and intake manifold.

  1. Properly relieve the fuel system pressure as outlined in Fuel System .
  2.  
  3. Disconnect the negative battery cable and remove the air cleaner assembly.
  4.  
  5. Detach the control cables from the connections from the throttle body portion of the plenum.
  6.  
  7. Unfasten the retaining bolts, then remove the fuel rail cover.
  8.  
  9. If necessary, disconnect the vacuum module line at the intake manifold.
  10.  
  11. Disconnect the fuel feed line and return line from the fuel rail assembly; be sure to use a backup wrench on the inlet fitting to prevent turning.
  12.  
  13. Disconnect the heater hose from the lower intake manifold.
  14.  
  15. Disconnect the PCV valve and vacuum line from the throttle body portion of the plenum (upper intake manifold).
  16.  
  17. Tag and detach the AIR solenoid, EGR valve, and TPS connectors.
  18.  
  19. Unfasten the retaining bolts, then remove the EGR valve.
  20.  
  21. Remove the fuel line bracket from the throttle body portion of the plenum.
  22.  
  23. Loosen the throttle body heater hose clamp from the upper intake manifold (plenum).
  24.  
  25. Disconnect the canister purge solenoid and MAP sensor connectors.
  26.  
  27. Carefully disconnect the vacuum hoses from the vacuum tee on the plenum.
  28.  
  29. Remove the wiring loom bracket for the rear spark plug cables.
  30.  
  31. Unfasten the plenum (upper manifold) support bracket nuts.
  32.  
  33. Remove the plenum mounting bolts and remove the intake plenum. Remove and discard the gaskets.
  34.  
  35. Remove the vacuum line at the pressure regulator. Remove the fuel rail assembly retaining bolts.
  36.  
  37. Push in the wire connector clip, while pulling the connector away from the injector.
  38.  
  39. Remove the fuel rail assembly and cover all openings with masking tape to prevent dirt from entering.
  40.  
  41. Detach the electrical connector, then remove the temperature sensor.
  42.  
  43. Remove the heater hose pipe bracket at the thermostat housing.
  44.  
  45. Disconnect the radiator hose from thermostat housing.
  46.  
  47. Unfasten the mounting bolts, then remove the lower intake manifold. Remove and discard the gaskets.
  48.  

To install:
  1. Thoroughly clean and dry all mating surfaces and install new intake manifold gaskets.
  2.  

Tighten the manifold bolts evenly. DO NOT tighten one side or end of the manifold fully.

  1. Position the intake manifold. Insert new rubber isolators into manifold flange and tighten the mounting evenly bolts to 18-22 ft. lbs. (25-30 Nm). Start with center bolts and work outwards in a circular pattern.
  2.  
  3. Install the heater hose pipe bracket to the thermostat housing.
  4.  
  5. Install the temperature sensor and attach the connector.
  6.  
  7. Connect the radiator hose to thermostat housing.
  8.  
  9. Install the fuel rail assembly and secure with the retaining bolts.
  10.  
  11. Connect the vacuum line to the pressure regulator.
  12.  
  13. Install the intake plenum, using new gaskets and install the retaining bolts. Tighten the bolts 18-22 ft. Lbs. (25-30 Nm), starting in the center and working outwards in a circular pattern.
  14.  
  15. Install the plenum support bracket nuts.
  16.  
  17. Install the wiring loom bracket for the rear spark plug cables.
  18.  
  19. Carefully connect the vacuum hoses to the vacuum tee on the plenum.
  20.  
  21. Connect the canister purge solenoid and MAP sensor connectors.
  22.  
  23. Tighten the throttle body hose clamp.
  24.  
  25. Install the fuel line bracket to the throttle body portion of the plenum.
  26.  
  27. Install the EGR valve.
  28.  
  29. Attach the AIR solenoid, EGR valve, and TPS connectors.
  30.  
  31. Connect the PCV valve and vacuum line to the throttle body portion of the plenum.
  32.  
  33. Attach the heater hose to the intake manifold.
  34.  
  35. Connect the fuel feed line and return line to the fuel rail assembly and install the fuel rail cover.
  36.  
  37. Fasten the control cables to the throttle body portion of the plenum.
  38.  
  39. Install the air cleaner assembly.
  40.  
  41. Fill the cooling system. Connect the negative battery cable.
  42.  
  43. Run the engine until it reaches normal operating temperature and check for coolant and oil leaks.
  44.  

3.8L Engine

See Figures 23 and 24



Click image to see an enlarged view

Fig. Fig. 23: Removal of the upper and lower intake manifold assemblies-3.8L engine



Click image to see an enlarged view

Fig. Fig. 24: Lower intake manifold tightening sequence-3.8L engine

  1. Properly relieve the fuel system pressure as outlined in Fuel System of this repair guide.
  2.  
  3. Disconnect the negative battery cable. Place a clean drainPan under the radiator, open the drain cock and drain the cooling system.
  4.  
  5. Remove the air cleaner assembly and the fuel injector sight shield.
  6.  
  7. Disconnect the cables from the throttle body and mount bracket.
  8.  
  9. Remove the coolant recovery reservoir.
  10.  
  11. Remove the inner fender electrical cover on the right side.
  12.  
  13. Remove the right rear crossover pipe heat shield.
  14.  
  15. Disconnect the fuel lines from the fuel rail and from the cable bracket.
  16.  
  17. Remove the alternator and brace.
  18.  
  19. Remove the throttle body cable mounting bracket with the vacuum lines and disconnect the vacuum lines.
  20.  
  21. Tag and detach the electrical connections at the throttle body and both banks of fuel injectors.
  22.  
  23. Disconnect the vacuum hoses from the canister purge solenoid valve and transaxle module and intake connection.
  24.  
  25. Unbolt the power steering pump and move forward. DO NOT disconnect the fluid lines.
  26.  
  27. Tag and disconnect the spark plug wires position lay aside.
  28.  
  29. Disconnect the coolant bypass hose from the intake manifold.
  30.  
  31. Remove the solenoid valve mounting bracket and power steering support brace from the intake manifold.
  32.  
  33. Disconnect the heater pipes from the intake and front cover.
  34.  
  35. Remove the alternator support brace from the intake.
  36.  
  37. Disconnect the upper radiator hose from the housing.
  38.  
  39. Remove the thermostat housing and thermostat from the intake.
  40.  
  41. Detach the electrical connector from the temperature sensor and sensor switch.
  42.  
  43. Unfasten the intake manifold bolts, then remove the manifold as an assembly. Remove and discard the gaskets.
  44.  
  45. If separating the upper manifold from the lower, proceed as follows:
    1. Remove the fuel rail and fuel injectors.
    2.  
    3. Detach the coolant sensor switch.
    4.  
    5. Remove the manifold end cap cover.
    6.  
    7. Remove the upper intake manifold and throttle body assembly from the lower manifold. Remove and discard the gaskets.
    8.  

  46.  

To install:
  1. Thoroughly clean all gasket mating surfaces.
  2.  
  3. If replacing the upper manifold, proceed as follows:
    1. Apply a 1 / 16 in. bead of Loctite® Instant Gasket Eliminator 51845 or equivalent to the lower manifold mating surface. Make sure to circle all bolt holes.
    2.  
    3. Carefully lower the upper manifold and throttle body assembly onto the lower manifold.
    4.  
    5. Tighten the upper manifold retaining bolts to 19 ft. lbs. (26 Nm).
    6.  
    7. Install the manifold end cap cover and the coolant sensor switch.
    8.  
    9. Install the fuel injectors and rail to the manifold assembly.
    10.  

  4.  
  5. Clean the mating surfaces and install the intake manifold gaskets and seals. Apply sealer to the ends of the of the intake manifold seals.
  6.  
  7. Position the intake manifold and apply a suitable thread lock compound to the bolt threads. Tighten the retaining bolts to 88 inch lbs. (10 Nm), twice, in the sequence shown in the accompanying figure.
  8.  
  9. Attach the electrical connector to the temperature sensor and sensor switch.
  10.  
  11. Install the thermostat housing and thermostat with a new gasket.
  12.  
  13. Connect the alternator support brace to the intake.
  14.  
  15. Install the solenoid valve mounting bracket and power steering support brace to the intake manifold.
  16.  
  17. Connect the heater pipes to the intake and front cover.
  18.  
  19. Attach the coolant bypass hose to the intake manifold.
  20.  
  21. Install the power steering pump support bracket and tighten to 37 ft. lbs. (50 Nm).
  22.  
  23. Install the spark plug wires on both sides.
  24.  
  25. Install the belt tensioner pulley and tighten to 33 ft. lbs. (45 Nm).
  26.  
  27. Install the power steering pump.
  28.  
  29. Connect the vacuum hoses to the canister purge solenoid valve and transaxle module and intake connection.
  30.  
  31. Attach the electrical connections at the throttle body and both banks of fuel injectors.
  32.  
  33. Install the alternator and brace.
  34.  
  35. Connect the throttle body cable mounting bracket with the vacuum lines.
  36.  
  37. Install the right rear crossover pipe heat shield.
  38.  
  39. Install the cables to the throttle body.
  40.  
  41. Connect the fuel lines to the fuel rail and mount bracket.
  42.  
  43. Install the inner fender electrical cover on the right side.
  44.  
  45. Install the coolant recovery reservoir and upper radiator hose. Fill the cooling system.
  46.  
  47. Install the air cleaner assembly and the fuel injector sight shield.
  48.  
  49. Connect the negative battery cable.
  50.  

 
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