GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2000 🢒 Blazer - 4WD 🢒 Engine 🢒 Engine Mechanical - 4.3L 🢒 Intake Manifold Replacement

Intake Manifold Replacement Upper

Removal Procedure

Important: The upper intake does not have to be removed to remove the lower intake manifold.

  1. Remove the air cleaner outlet duct from the throttle body. Refer to Air Cleaner Outlet Duct Replacement In Engine Controls.
  2. Disconnect the accelerator control cable from the throttle shaft and the accelerator cable bracket. Refer to Accelerator Control Cable Replacement in Engine Controls.
  3. Disconnect the cruise control cable, if equipped from the throttle shaft and the accelerator cable bracket. Refer to Cruise Control Cable Replacement in Cruise Control.

    4. Object Number: 346148 Size: SH
  4. Disconnect the vacuum hose from the intake manifold for the vacuum tank.
  5. Remove the power brake booster vacuum hose.

    6. Object Number: 516898 Size: SH
  6. Disconnect the following electrical connectors:
    7. • The A/C compressor clutch (1)
    • The A/C compressor cutoff switch (5), if equipped
    • The throttle position (TP) sensor (2)
    • The idle air control (IAC) motor (3)

    Object Number: 516916 Size: SH
  7. Disconnect the following electrical connectors:
    8. • The fuel meter body assembly (1)
    • The manifold absolute pressure (MAP) sensor (3)
    • The EVAP canister purge solenoid valve (2)
  8. Remove the engine wire harness clip from the accelerator cable bracket.
  9. Move the engine wiring harness aside.

    10. Object Number: 398027 Size: SH
  10. Remove the accelerator cable bracket from the throttle body and the intake manifold.

    11. Object Number: 339439 Size: SH
  11. Remove the accelerator and cruise control cable bracket from the throttle body.

    12. Leave the accelerator and cruise control cables on the bracket.


    Object Number: 172995 Size: SH
  12. Remove the PCV valve hose assembly form the intake manifold and the valve rocker arm cover.

    13. Object Number: 339442 Size: SH
  13. Remove the bracket for the engine wiring harness from the intake manifold stud.
  14. Remove the fuel lines from the fuel meter body assembly. Refer to Fuel Hose/Pipes Replacement - Engine Compartment in Engine Controls.
  15. Remove the EVAP canister purge solenoid valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement in Engine Controls.

    16. Object Number: 516794 Size: SH
  16. Remove the studs for the upper intake manifold.
  17. Remove the upper intake manifold.

    18. Object Number: 516790 Size: SH
  18. Remove the upper intake manifold gasket from the groove.
  19. Discard the gasket.

    20. Object Number: 516773 Size: SH
  20. Remove the seal from the fuel meter body assembly.
  21. Discard the seal.

    22. Important: Do not immerse the assembled upper intake manifold in cleaning solvent.

  22. Clean all sealing surfaces and the inside of the upper intake manifold with a shop towel and cleaning solvent.
  23. Inspect the upper intake manifold for the following:
    24. • Cracks or other damage to the exterior
    • Cracking or damage to the gasket grooves
    • Loose or damaged bolt hole thread inserts
    • Damage to the throttle body mounting surface

    Object Number: 516804 Size: SH
  24. If replacing the upper intake manifold, turn and remove the power brake booster vacuum tube fitting from the upper intake manifold.
  25. Remove and discard the seal.

    26. Object Number: 516797 Size: SH
  26. If replacing the upper intake manifold, turn and remove the PCV valve cover from the upper intake manifold.
  27. Remove and discard the seal.
  28. Remove the throttle body if replacing the upper intake manifold. Refer to Throttle Body Assembly Replacement in Engine Controls.
  29. Remove the MAP sensor if replacing the upper intake manifold. Refer to Manifold Absolute Pressure Sensor Replacement in Engine Controls.

Installation Procedure

    Object Number: 516797 Size: SH
  1. Install the throttle body, if removed. Refer to Throttle Body Assembly Replacement in Engine Controls.
  2. Install the MAP sensor, if removed. Refer to Manifold Absolute Pressure Sensor Replacement in Engine Controls.
  3. Install the PCV valve cover, if removed, using the following procedure:
    4. 3.1. Install a NEW seal (O-ring) on the PCV valve cover.
    3.2. Lubricate the seal with clean engine oil.
    3.3. Install the PCV valve cover in the upper intake manifold.
    3.4. Turn and lock the PCV valve cover in position.

    Object Number: 516804 Size: SH
  4. Install the power brake booster vacuum tube fitting, if removed, using the following procedure:
    5. 4.1. Install a NEW seal (O-ring) on the power brake booster vacuum tube fitting.
    4.2. Lubricate the seal with clean engine oil.
    4.3. Install the power brake booster vacuum tube fitting in the upper intake manifold.
    4.4. Turn and lock the power brake booster vacuum tube fitting in position.

    Object Number: 516773 Size: SH
  5. Install a NEW seal on the fuel meter body assembly.
  6. Lubricate the seal with clean engine oil.

    7. Object Number: 516790 Size: SH
  7. Install a NEW upper intake manifold to lower intake manifold gasket in the groove of the upper intake manifold.

    8. Object Number: 516794 Size: SH
  8. Install the upper intake manifold onto the lower intake manifold.
  9. If reusing the fasteners, apply threadlock GM P/N 12345382 or equivalent to the threads of the upper intake manifold attaching bolts.

    10. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  10. Install the upper intake manifold attaching studs.

    11. Tightening

    1. Tighten the upper intake manifold attaching studs on the first pass to 5 N·m (44 lb in).
    2. Tighten the upper intake manifold attaching studs on the final pass to 9 N·m (80 lb in).
  11. Install the fuel lines to the fuel meter body assembly. Refer to Fuel Hose/Pipes Replacement - Engine Compartment in Engine Controls.
  12. Install the EVAP canister purge solenoid valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement in Engine Controls.

    13. Object Number: 339442 Size: SH
  13. Install the bracket for the engine wiring harness on the lower intake manifold stud.
  14. Install the engine wiring harness bracket nut.

    15. Tighten
    Tighten the engine wiring harness bracket nut to 12 N·m (106 lb in).


    Object Number: 339439 Size: SH
  15. Install the accelerator and cruise control cable bracket to the throttle body.
  16. Install the accelerator and cruise control cable bracket nuts.

    17. Tighten
    Tighten the accelerator and cruise control cable bracket nuts to 9 N·m (80 lb in).


    Object Number: 398027 Size: SH
  17. Install the accelerator control cable bracket to the throttle body and the intake manifold.

    18. Tighten
    Tighten the accelerator control cable bracket studs and nuts to 12 N·m (106 lb in).


    Object Number: 172995 Size: SH
  18. Connect the PCV valve hose assembly to the intake manifold and the valve rocker arm cover.

    19. Object Number: 516916 Size: SH
  19. Position the engine wiring harness.
  20. Install the wire harness clip to the accelerator cable bracket.
  21. Connect the following electrical connectors:
    22. • The fuel meter body assembly (1)
    • The manifold absolute pressure (MAP) sensor (3)
    • The EVAP canister purge solenoid valve (2)

    Object Number: 516898 Size: SH
  22. Connect the following electrical connectors:
    23. • The A/C compressor clutch (1)
    • The A/C compressor cutoff switch (5), if equipped
    • The throttle position (TP) sensor (2)
    • The idle air control (IAC) motor (3)

    Object Number: 346148 Size: SH
  23. Connect the vacuum hose from the vacuum tank to the intake manifold.
  24. Install the power brake booster vacuum hose to the intake manifold.
  25. Install the cruise control cable, if equipped to the throttle shaft and the bracket. Refer to Cruise Control Cable Replacement in Cruise Controls.
  26. Install the accelerator control cable to the throttle shaft and the bracket. Refer to Accelerator Control Cable Replacement in Engine Controls.
  27. Install the air cleaner outlet duct to the throttle body assembly. Refer to Air Cleaner Outlet Duct Replacement in Engine Controls.

Intake Manifold Replacement Lower

Removal Procedure

Important: You do not have to remove the upper intake manifold in order to remove the lower intake manifold.

  1. Disconnect the battery negative cable. Refer to Battery Replacement in Engine Electrical.
  2. Remove the air cleaner outlet duct from the throttle body. Refer to Air Cleaner Outlet Duct Replacement in Engine Controls.
  3. Disconnect the accelerator control cable from the throttle shaft and the accelerator cable bracket. Refer to Accelerator Control Cable Replacement in Engine Controls.
  4. Disconnect the cruise control cable, if equipped from the throttle shaft and the accelerator cable bracket. Refer to Cruise Control Cable Replacement in Cruise Control.

    5. Object Number: 346148 Size: SH
  5. Disconnect the vacuum hose from the intake manifold, if equipped with A/C.
  6. Disconnect the power brake booster vacuum hose

    7. Object Number: 182853 Size: SH
  7. Drain the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
  8. Remove the radiator inlet hose at the water outlet. Refer to Radiator Hose Replacement in Engine Cooling.
  9. Remove the heater hose from the intake manifold. Refer to Heater Hoses Replacement in Heating Ventilation and Air Conditioning.
  10. Remove the water pump inlet hose form the intake manifold.

    11. Object Number: 516916 Size: SH
  11. Disconnect the following electrical connectors:
    12. • The fuel meter body assembly (1)
    • The EVAP canister purge solenoid valve (2)
    • The manifold air pressure (MAP) sensor (3)

    Object Number: 516938 Size: SH
  12. Disconnect the following electrical connectors:
    13. • The exhaust gas recirculation (EGR) valve (3)
    • The ignition coil (2)
    • The ignition control module (ICM) (1)
    • The generator (4)

    Object Number: 516898 Size: SH
  13. Disconnect the following electrical connectors:
    14. • The idle air control (IAC) motor (3)
    • The throttle position (TP) sensor (2)
    • The A/C compressor cutoff switch, if equipped (5)
    • The A/C clutch switch, if equipped (1)
    • The engine coolant temperature (ECT) sensor (4)
  14. Remove the engine wiring harness clips from the brackets.
  15. Move the engine wiring harness aside.

    16. Object Number: 398027 Size: SH
  16. Remove the accelerator cable bracket from the throttle body and the intake manifold.

    17. Object Number: 339439 Size: SH
  17. Remove the accelerator and the cruise control cable bracket from the throttle bracket.

    18. Leave the accelerator and cruise control cables on the bracket.


    Object Number: 172995 Size: SH
  18. Disconnect the PCV hose assembly from the intake manifold and the valve rocker arm cover.
  19. Remove the EVAP canister purge solenoid valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement in Engine Controls.

    20. Object Number: 172982 Size: SH
  20. Remove the spark plug wire harness retainer from the exhaust gas recirculation (EGR) valve inlet pipe.
  21. Remove the clamp bolt for the EGR valve inlet pipe.
  22. Remove the EGR valve inlet pipe from the intake and the exhaust manifolds.
  23. Remove the distributor. Refer to Distributor Replacement in Engine Electrical.
  24. Disconnect the fuel supply and return pipes at the rear of the intake manifold. Refer to Fuel Hose/Pipes Replacement - Engine Compartment in Engine Controls.

    25. Object Number: 340090 Size: SH

    Important: Do not discharge the refrigerant.

  25. Perform the following in order to remove the left front bolt for the intake manifold:
    26. 25.1. Remove the drive belt. Refer to Drive Belt Replacement .
    25.2. Loosen the nut for the power steering pump rear bracket at the side of the engine.
    25.3. Remove the secondary air injection (AIR) reactor pipe bracket nut from the power steering pump rear bracket front stud, if equipped.
    25.4. Remove the nut for the power steering pump rear bracket at the front of the engine.
    25.5. Remove the bolts and the nut for the power steering pump mounting bracket.
    25.6. Leave the A/C compressor, if equipped, and the power steering pump on the power steering pump mounting bracket.
    25.7. Slide the power steering pump bracket forward to access the bolt at the front of the intake manifold.
  26. Remove the lower intake manifold. Refer to Intake Manifold Removal .
  27. Disassemble the intake manifold assembly if replacing the lower intake manifold. Refer to Intake Manifold Disassemble .

    28. Important: Do not immerse the assembled intake manifold in cleaning solvent.

  28. Clean all sealing surfaces. Refer to Intake Manifold Cleaning and Inspection .

Installation Procedure
  1. Assemble the intake manifold assembly if replacing the lower intake manifold. Refer to Intake Manifold Assemble .
  2. Install the lower intake manifold. Refer to Intake Manifold Installation .

    3. Object Number: 340090 Size: SH
  3. Position the power steering pump mounting bracket.
  4. Loosely install the power steering pump mounting bracket bolts and nuts.

    5. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  5. Install the nut for the power steering pump rear bracket at the front of the engine.

    6. Tighten
    Tighten the power steering pump mounting bracket bolts and the power steering pump rear bracket nuts to 41 N·m (30 lb ft).

  6. Install the AIR reactor pipe bracket nut to the power steering pump rear bracket front stud, if equipped.

    7. Tighten
    Tighten the AIR reactor pipe bracket nut to 41 N·m (30 lb ft).

  7. Install the drive belt. Refer to Drive Belt Replacement .
  8. Install the fuel supply and return pipes to the rear of the intake manifold. Refer to Fuel Hose/Pipes Replacement - Engine Compartment in Engine Controls.

    9. Object Number: 334551 Size: SH

    Important: In order to install the distributor for the correct engine timing, position the engine to number one cylinder top dead center.

  9. Remove the spark plug for number one cylinder.
  10. Rotate the crankshaft until number one cylinder is in the compression stroke.
  11. Align the two reference marks on the crankshaft balancer (1) and (4) with the two alignment marks (2) and (3) on the front cover.
  12. Install the spark plug. Refer to Spark Plug Replacement in Engine Electrical.
  13. Install the distributor. Refer to Distributor Replacement in Engine Electrical.
  14. Install the EVAP canister purge solenoid valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement in Engine Controls.

    15. Object Number: 172982 Size: SH
  15. Install the EGR valve inlet pipe to the intake manifold and the exhaust manifold.

    16. Tighten

    1. Tighten the EGR valve inlet pipe intake manifold nut to 25 N·m (18 lb ft).
    2. Tighten the EGR valve inlet pipe exhaust manifold nut to 30 N·m (22 lb ft).
    3. Tighten the EGR valve inlet pipe clamp bolt 25 N·m (18 lb ft).
  16. Install the spark plug wire harness retainer on the EGR valve inlet pipe.

    17. Object Number: 172995 Size: SH
  17. Install the PCV hose assembly to the intake manifold and the valve rocker arm cover.

    18. Object Number: 339439 Size: SH
  18. Install the accelerator cable and cruise control cable bracket to the throttle body.

    19. Tighten
    Tighten the accelerator cable and cruise control bracket nuts to 9 N·m (80 lb in).


    Object Number: 398027 Size: SH
  19. Install the accelerator cable bracket to the intake manifold and the throttle body.

    20. Tighten
    Tighten the accelerator cable bracket studs and nuts to 12 N·m (106 lb in).


    Object Number: 516898 Size: SH
  20. Position the engine wiring harness.
  21. Install the engine wiring harness clips in the brackets.
  22. Connect the following electrical connectors:
    23. • The idle air control (IAC) motor (3)
    • The throttle position (TP) sensor (2)
    • The A/C compressor cutoff switch, if equipped (5)
    • The A/C clutch switch, if equipped (1)
    • The engine coolant temperature (ECT) sensor (4)

    Object Number: 516916 Size: SH
  23. Connect the following electrical connectors:
    24. • The fuel meter body assembly (1)
    • The EVAP canister purge solenoid valve (2)
    • The manifold air pressure (MAP) sensor (3)

    Object Number: 516938 Size: SH
  24. Connect the following electrical connectors:
    25. • The exhaust gas recirculation (EGR) valve (3)
    • The ignition coil (2)
    • The ignition control module (ICM) (1)
    • The generator (4)

    Object Number: 346148 Size: SH
  25. Connect the power brake booster vacuum hose.
  26. Connect the vacuum hose to the intake manifold, if equipped with A/C.

    27. Object Number: 182853 Size: SH
  27. Install the water pump inlet hose to the intake manifold.
  28. Install the heater hose to the intake manifold. Refer to Heater Hoses Replacement in Heating Ventilation and Air Conditioning.
  29. Install the radiator inlet hose to the water outlet. Refer to Radiator Hose Replacement in Engine Cooling.
  30. Install the accelerator control cable to the bracket and the throttle shaft. Refer to Accelerator Control Cable Replacement in Engine Controls.
  31. Install the cruise control cable, if equipped to the bracket and the throttle shaft. Refer to Cruise Control Cable Replacement in Cruise Control.
  32. Fill the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
  33. Install the air cleaner outlet duct to the throttle body. Refer to Air Cleaner Outlet Duct Replacement in Engine Controls.
  34. Connect the battery negative cable. Refer to Battery Replacement in Engine Electrical.