GM Malibu/Cutlass 1997-2000

Intake Manifold

Print


CAUTION
Observe all applicable safety precautions when working around fuel. Whenever servicing the fuel system, always work in a well ventilated area. Do not allow fuel spray or vapors to come in contact with a spark or open flame. Keep a dry chemical fire extinguisher near the work area. Always keep fuel in a container specifically designed for fuel storage; also, always properly seal fuel containers to avoid the possibility of fire or explosion.


CAUTION
Never open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

2.4L Engine
  1. Properly relieve the fuel system pressure, as outlined in .
  2.  


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. Disconnect the negative battery cable, then properly drain the cooling system.
  2.  
  3. Tag and detach the electrical connectors from the following components:

    Manifold Absolute Pressure (MAP) sensor
     
    Intake Air Temperature (IAT) sensor
     
    EVAP canister purge solenoid
     
    Fuel injector harness
     

  4.  
  5. Label and disconnect the vacuum hoses from the fuel regulator and EVAP canister purge solenoid to canister.
  6.  
  7. Unfasten the air cleaner duct.
  8.  
  9. Remove the accelerator control cable bracket.
  10.  
  11. Remove the stud-ended alternator mount bolt, then detach the EGR pipe from the EGR adapter.
  12.  



Click image to see an enlarged view

Fig. Detach the EGR pipe from the adapter-2.4L engine

  1. 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.
  2.  
  3. Raise and safely support the front of the vehicle securely on jackstands.
  4.  
  5. Remove the intake manifold support brace.
  6.  
  7. Carefully lower the vehicle.
  8.  



Click image to see an enlarged view

Fig. On the 2.4L engine, you must raise the vehicle for access to the manifold brace

  1. Unfasten the manifold retaining nuts and bolts, then remove the intake manifold from the engine.
  2.  


NOTE
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.  


NOTE
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 specifications found in the chart in this section.
  2.  



Click image to see an enlarged view

Fig. Intake manifold bolt tightening sequence and specifications for the 2.4L engine

  1. Raise and safely support the front of the vehicle securely on jackstands.
  2.  
  3. Install the intake manifold brace and retainers.
  4.  
  5. Carefully lower the vehicle.
  6.  
  7. If removed, position the oil fill tube in its cylinder block opening. Align the fill tube so it is in its relative proper installed 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.
  8.  
  9. Attach the EGR pipe to the adapter; tighten the fasteners to 19 ft. lbs. (26 Nm). Install the stud-ended alternator bolt.
  10.  
  11. Install the accelerator control cable bracket.
  12.  
  13. Connect the vacuum hoses to the fuel regulator and EVAP canister purge solenoid.
  14.  
  15. Attach all electrical connectors, as tagged during removal.
  16.  
  17. Install the air cleaner duct.
  18.  
  19. Refill the coolant to it's proper level.
  20.  
  21. Connect the negative battery cable, then start the engine and inspect for leaks.
  22.  

3.1L Engine

NOTE
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, as outlined in .
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the 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. Exploded view of the upper and lower intake manifold and fasteners

  1. Detach the upper engine wiring harness connectors from the following components:

    Throttle Position (TP) sensor
     
    Idle Air Control (IAC) valve
     
    Fuel injectors
     
    Engine Coolant Temperature (ECT) 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 the 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 a suitable engine support fixture tool.
  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 from the 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.  


NOTE
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.  


NOTE
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 their original locations and tighten to the proper specifications.
  2.  
  3. Install lower the intake manifold attaching bolts. Apply sealant 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 the thermostat housing.
  12.  
  13. Connect the 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.  

 
label.common.footer.alt.autozoneLogo