GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2000 🢒 Chevy C Silverado - 2WD 🢒 Engine 🢒 Engine Controls - 4.3L 🢒 Intake Manifold Replacement

Intake Manifold Replacement Upper

Removal Procedure

Important: It is not necessary to remove the upper intake manifold in order to remove the lower intake manifold.

  1. Disconnect the PCV hose from the air cleaner outlet duct.
  2. Remove the air cleaner outlet duct from the throttle body and the air cleaner assembly. Refer to Air Cleaner Outlet Duct Replacement in Engine Controls - 4.3L.
  3. Disconnect the accelerator control cable from the throttle shaft and the accelerator cable bracket at the side of the throttle body. Refer to Accelerator Control Cable Replacement in Engine Controls - 4.3L.
  4. Disconnect the cruise control cable, if equipped from the throttle shaft and the accelerator cable bracket at the side of the throttle body. Refer to Cruise Control Cable Replacement in Cruise Control.

    5. Object Number: 398030 Size: SH
  5. Remove the engine wiring harness clip from the accelerator control cable bracket.
  6. Remove the accelerator control cable bracket with the accelerator control cable and the cruise control cable from the throttle body.
  7. Move and secure the accelerator control cable and the cruise control cable out of the way.

    8. Object Number: 398868 Size: SH
  8. Disconnect the secondary air injection (AIR) crossover pipe from the AIR pipe assemblies, if equipped.
  9. Remove the AIR crossover pipe, if equipped.

    10. Object Number: 491821 Size: SH
  10. Disconnect the following electrical connections:
    11. • The A/C compressor clutch (1), if equipped
    • The A/C pressure switch (4), if equipped
    • The EGR valve (2)

    Object Number: 491817 Size: SH
  11. Disconnect the following electrical connections:
    12. • The throttle position (TP) sensor (1)
    • The idle air control (IAC) motor (2)
    • The fuel meter body assembly connector (3)

    Object Number: 491816 Size: SH
  12. Disconnect the following electrical connections:
    13. • The manifold absolute pressure (MAP) sensor (2)
    • The EVAP canister purge solenoid valve (1)

    Object Number: 310241 Size: SH
  13. Remove the two nuts holding the engine wiring harness bracket to the upper intake manifold studs.
  14. Remove the engine wiring harness bracket from the studs.

    15. Object Number: 310243 Size: SH
  15. Remove the nut holding the engine wiring harness bracket to the stud at the EVAP canister purge solenoid valve.
  16. Remove the nut and the ground wire from the engine wiring harness bracket stud at the rear of the right cylinder head.
  17. Remove the stud holding the engine wiring harness bracket.
  18. Move the engine wiring harness and the engine wiring harness brackets aside.
  19. Remove the EVAP canister purge solenoid valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement in Engine Controls - 4.3L.

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

    21. Object Number: 346148 Size: SH
  21. Disconnect the power brake booster vacuum hose from the intake manifold.

    22. Object Number: 398033 Size: SH
  22. Remove the accelerator control cable bracket from the intake manifold and the throttle body.
  23. Remove the fuel lines from the fuel meter body assembly. Refer to Fuel Hose/Pipes Replacement - Engine Compartment in Engine Controls - 4.3L.

    24. Object Number: 516794 Size: SH
  24. Remove the studs for the upper intake manifold.
  25. Remove the upper intake manifold.

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

    28. Object Number: 516773 Size: SH
  28. Remove the seal (O-ring) from the fuel meter body assembly.
  29. Discard the seal.

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

  30. Clean all sealing surfaces and the inside of the upper intake manifold with a shop towel and cleaning solvent.
  31. Inspect the upper intake manifold for the following:
    32. • Cracks or other damage to the exterior
    • Cracking or damage to the gasket grooves
    • Loose or damaged bolt hole thread inserts

    Object Number: 516797 Size: SH
  32. If replacing the upper intake manifold, turn and remove the power brake booster vacuum tube fitting from the upper intake manifold.
  33. Remove and discard the seal (O-ring).

    34. Object Number: 516804 Size: SH
  34. If replacing the upper intake manifold, turn and remove the PCV valve cover from the upper intake manifold.
  35. Remove and discard the seal (O-ring).
  36. Remove the throttle body if replacing the upper intake manifold. Refer to Throttle Body Assembly Replacement in Engine Controls - 4.3L.
  37. Remove the MAP sensor if replacing the upper intake manifold. Refer to Manifold Absolute Pressure Sensor Replacement in Engine Controls - 4.3L.

Installation Procedure

    Object Number: 516804 Size: SH
  1. Install the throttle body, if removed. Refer to Throttle Body Assembly Replacement in Engine Controls - 4.3L.
  2. Install the MAP sensor, if removed. Refer to Manifold Absolute Pressure Sensor Replacement in Engine Controls - 4.3L.
  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: 516797 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. Tighten

    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 - 4.3L.
  12. Install the EVAP canister purge solenoid valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement in Engine Controls - 4.3L.

    13. Object Number: 398033 Size: SH
  13. Install the accelerator control cable bracket to the throttle body and the intake manifold.

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


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

    15. Object Number: 346148 Size: SH
  15. Connect the power brake booster vacuum hose to the intake manifold.

    16. Object Number: 310243 Size: SH
  16. Position the engine wiring harness and engine wiring harness brackets.
  17. Install the stud holding the engine wiring harness bracket to the rear of the right cylinder head.

    18. Tighten
    Tighten the engine wiring harness bracket stud to 25 N·m (18 lb ft).

  18. Install the nut holding the engine wiring harness bracket to the stud at the EVAP canister purge solenoid valve.

    19. Tighten
    Tighten the engine wiring harness bracket nut to 9 N·m (80 lb in).

  19. Install the nut and the ground wire on the engine wiring harness bracket stud at the rear of the right cylinder head.

    20. Tighten
    Tighten the ground wire nut to 16 N·m (12 lb ft).


    Object Number: 310241 Size: SH
  20. Install the engine wiring harness bracket on the upper intake manifold studs.
  21. Install the engine wiring harness bracket nuts.

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


    Object Number: 491821 Size: SH
  22. Connect the following electrical connections:
    23. • The A/C compressor clutch (1), if equipped
    • The A/C pressure switch (4), if equipped
    • The EGR valve (2)

    Object Number: 491817 Size: SH
  23. Connect the following electrical connections:
    24. • The throttle position (TP) sensor (1)
    • The idle air control (IAC) motor (2)
    • The fuel meter body assembly connector (3)

    Object Number: 491816 Size: SH
  24. Connect the following electrical connections:
    25. • The manifold absolute pressure (MAP) sensor (2)
    • The EVAP canister purge solenoid valve (1)

    Object Number: 398030 Size: SH
  25. Install the accelerator control cable bracket with the accelerator control cable and the cruise control cable and the nuts to the throttle body.

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

  26. Install the engine wiring harness clip to the accelerator control cable bracket.
  27. Install the cruise control cable, if equipped to the throttle shaft and the accelerator control cable bracket. Refer to Cruise Control Cable Replacement in Cruise Control.
  28. Install the accelerator control cable to the throttle shaft and the accelerator control cable bracket. Refer to Accelerator Control Cable Replacement in Engine Controls - 4.3L.

    29. Object Number: 398868 Size: SH
  29. Connect the AIR crossover pipe to the AIR pipe assemblies.
  30. Install the air cleaner outlet duct to the throttle body and the air cleaner assembly. Refer to Air Cleaner Outlet Duct Replacement in Engine Controls - 4.3L.
  31. Connect the PCV hose to the air cleaner outlet duct.

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 Negative Cable Disconnection and Connection in Engine Electrical.
  2. Drain the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
  3. Disconnect the PCV hose from the air cleaner outlet duct.
  4. Remove the air cleaner outlet duct from the throttle body and the air cleaner assembly. Refer to Air Cleaner Outlet Duct Replacement in Engine Controls - 4.3L.
  5. Remove the accelerator control cable from the throttle shaft and the accelerator control cable bracket at the side of the throttle body. Refer to Accelerator Control Cable Replacement in Engine Controls - 4.3L.
  6. Disconnect the cruise control cable, if equipped from the throttle shaft and the accelerator control cable bracket at the side of the throttle body. Refer to Cruise Control Cable Replacement in Cruise Control.

    7. Object Number: 398030 Size: SH
  7. Remove the engine wiring harness and clip from the accelerator control cable bracket.
  8. Remove the accelerator control cable bracket with the accelerator control cable and the cruise control cable from the throttle body.
  9. Move and secure the accelerator control cable bracket with the cables out of the way.

    10. Object Number: 398868 Size: SH
  10. Disconnect the secondary air injection (AIR) crossover pipe from the AIR pipe assemblies, if equipped.
  11. Remove the AIR crossover pipe.

    12. Object Number: 491816 Size: SH
  12. Disconnect the following electrical connectors:
    13. • The EVAP canister purge solenoid valve (1)
    • The manifold absolute pressure (MAP) sensor (2)
    • The ignition control module (ICM) (4)
    • The ignition coil (3)

    Object Number: 491821 Size: SH
  13. Disconnect the following electrical connectors:
    14. • The A/C pressure switch (4), if equipped
    • The A/C compressor clutch (1), if equipped
    • The exhaust gas recirculation (EGR) valve (2)
    • The generator battery positive cable (3)

    Object Number: 491817 Size: SH
  14. Disconnect the following electrical connectors:
    15. • The fuel meter body assembly (3)
    • The throttle position (TP) sensor (1)
    • The idle air control (IAC) motor (2)
    • The engine coolant temperature (ECT) sensor (4)

    Object Number: 310243 Size: SH
  15. Remove the nut holding the engine wiring harness bracket to the EVAP purge solenoid valve stud.
  16. Remove the nut holding the ground wire to the engine wiring harness bracket stud at the rear of the right cylinder head.
  17. Remove the stud holding the engine wiring harness bracket.

    18. Object Number: 310241 Size: SH
  18. Remove the two nuts holding the engine wiring harness bracket to the upper intake manifold studs.
  19. Remove the engine wiring harness bracket from the studs.
  20. Move the engine wiring harness with the brackets aside.

    21. Object Number: 182853 Size: SH
  21. Remove the radiator inlet hose at the water outlet. Refer to Radiator Inlet Hose Replacement in Engine Cooling. .
  22. Remove the water pump inlet hose from the intake manifold.
  23. Remove the heater hoses from the engine. Refer to Heater Hoses Replacement in Heating Ventilation and Air Conditioning.
  24. Remove the distributor. Refer to Distributor Replacement in Engine Electrical.
  25. 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 - 4.3L.

    26. Object Number: 172995 Size: SH
  26. Disconnect PCV valve hose assembly from the intake manifold and the valve rocker arm cover.

    27. Object Number: 346148 Size: SH
  27. Disconnect the power brake booster vacuum hose from the intake manifold.
  28. Disconnect the hose to the EVAP canister purge solenoid valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement in Engine Controls - 4.3L.

    29. Object Number: 172982 Size: SH
  29. Remove the spark plug wire harness retainer from the exhaust gas recirculation (EGR) valve inlet pipe.
  30. Remove the clamp bolt for the EGR valve inlet pipe.
  31. Remove the EGR valve inlet pipe from the intake and the exhaust manifolds.

    32. Object Number: 340090 Size: SH
  32. In order to remove the front intake manifold bolt, perform the following:
    33. 32.1. Remove the drive belt. Refer to Drive Belt Replacement .
    32.2. Loosen the power steering pump rear bracket side nut.
    32.3. Remove the power steering pump rear bracket front nut.
    32.4. Remove the bolts and the nut for the power steering pump mounting bracket.
    32.5. Leave the A/C compressor, if equipped, and the power steering pump on the bracket.
    32.6. Slide the power steering pump mounting bracket forward to access the bolt at the front of the intake manifold.
  33. Remove the lower intake manifold. Refer to Intake Manifold Removal .

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

  34. Clean all sealing surfaces and the intake manifold. Refer to Intake Manifold Clean and Inspect .
  35. If the intake manifold requires replacement refer to Intake Manifold Disassemble and Intake Manifold Assemble .

Installation Procedure
  1. Install the lower intake manifold. Refer to Intake Manifold Installation .

    2. Object Number: 340090 Size: SH
  2. Position the power steering pump mounting bracket.
  3. Install the three bolts and the nut.

    4. 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.

  4. Install the front nut for the power steering pump rear bracket.

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

  5. Install the drive belt. Refer to Drive Belt Replacement .

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

    7. 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).
  7. Install the spark plug wire harness retainer on the EGR valve inlet pipe.

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

    9. Object Number: 346148 Size: SH
  9. Install the power brake booster vacuum hose to the intake manifold.
  10. Install the EVAP canister purge solenoid valve hose. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement in Engine Controls - 4.3L.
  11. 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 - 4.3L.

    12. 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.

  12. Remove the spark plug for number one cylinder.
  13. Rotate the crankshaft until number one cylinder is in the compression stroke.
  14. Align the two reference marks on the crankshaft balancer (1) and (4) with the two alignment marks (2) and (3) on the front cover.
  15. Install the spark plug. Refer to Spark Plug Replacement in Engine Electrical.
  16. Install the distributor. Refer to Distributor Replacement in Engine Electrical.

    17. Object Number: 182853 Size: SH
  17. Install the water pump inlet hose to the intake manifold.
  18. Install the heater hoses to the engine. Refer to Heater Hoses Replacement in Heating Ventilation and Air Conditioning.
  19. Install the radiator inlet hose to the water outlet. Refer to Radiator Inlet Hose Replacement in Engine Cooling.
  20. Refill the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.

    21. Object Number: 310243 Size: SH
  21. Position the engine wiring harness and the engine wiring harness brackets.
  22. Install the stud at the rear of the right cylinder head for the engine wiring harness bracket.

    23. Tighten
    Tighten the engine wiring harness bracket stud to 25 N·m (18 lb ft).

  23. Install the nut holding the engine wiring harness bracket to the EVAP purge canister solenoid stud.

    24. Tighten
    Tighten the engine wiring harness bracket nut to 9 N·m (80 lb in).

  24. Install the nut and the ground wire to engine wiring harness bracket stud at the rear of the right cylinder head.

    25. Tighten
    Tighten the ground wire nut to 16 N·m (12 lb ft).


    Object Number: 310241 Size: SH
  25. Install the nuts and the engine wiring harness bracket to the upper intake manifold studs.

    26. Tighten
    Tighten the engine wiring harness bracket nuts 12 N·m (106 lb in).


    Object Number: 491816 Size: SH
  26. Connect the following electrical connectors:
    27. • The EVAP canister purge solenoid valve (1)
    • The manifold absolute pressure (MAP) sensor (2)
    • The ignition control module (ICM) (4)
    • The ignition coil (3)

    Object Number: 491821 Size: SH
  27. Connect the following electrical connectors:
    28. • The A/C pressure switch (4), if equipped
    • The A/C compressor clutch (1), if equipped
    • The exhaust gas recirculation (EGR) valve (2)
    • The generator battery positive cable (3)

    Object Number: 491817 Size: SH
  28. Connect the following electrical connectors:
    29. • The fuel meter body assembly (3)
    • The throttle position (TP) sensor (1)
    • The idle air control (IAC) motor (2)
    • The engine coolant temperature (ECT) sensor (4)

    Object Number: 398868 Size: SH
  29. Connect the AIR crossover pipe to the AIR pipe assemblies.

    30. Object Number: 398030 Size: SH
  30. Install the accelerator control cable bracket with the accelerator control cable and the cruise control cable and the nuts to the throttle body.

    31. Tighten
    Tighten the nuts to 9 N·m (80 lb in).

  31. Install the accelerator cable to the throttle shaft the accelerator control cable bracket. Refer to Accelerator Control Cable Replacement in Engine Controls - 4.3L.
  32. Install the cruise control cable, if equipped to the throttle shaft the accelerator control cable bracket. Refer to Cruise Control Cable Replacement in Cruise Control.
  33. Install the engine wiring harness and clip to the accelerator control cable bracket.
  34. Install the air cleaner outlet duct to the throttle body and the air cleaner assembly. Refer to Air Cleaner Outlet Duct Replacement in Engine Controls - 4.3L.
  35. Connect the PCV hose to the air cleaner outlet duct.
  36. Connect the battery negative cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.