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

Intake Manifold Replacement Upper

Removal Procedure

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

  1. Remove the engine cover. Refer to Engine Cover Replacement .
  2. Remove the air cleaner outlet duct from the throttle body. Refer to Air Cleaner Outlet Duct Replacement in Engine Controls.
  3. Remove the A/C compressor hose assembly. Refer to Auxiliary Air Conditioning Compressor and Condenser Hose Replacement .
  4. Disconnect the accelerator control cable from the throttle shaft and the accelerator control cable bracket. Refer to Accelerator Control Cable Replacement in Engine Controls.
  5. Disconnect the cruise control cable, if equipped from the throttle shaft and the accelerator control cable bracket. Refer to Cruise Control Cable Replacement in Cruise Control.

    6. Object Number: 172995 Size: SH
  6. Remove the PCV valve hose assembly from the intake manifold and the valve rocker arm cover.
  7. Remove the nut holding the engine wiring harness bracket to the intake manifold stud.
  8. Remove the engine wiring harness bracket from the stud.

    9. Object Number: 527368 Size: SH
  9. Disconnect the following electrical connectors:
    10. • The A/C compressor clutch, if equipped (1)
    • The A/C high pressure cutoff switch, if equipped (5)
    • The throttle position (TP) sensor (2)
    • The idle air control (IAC) motor (3)
    • The fuel meter body assembly connector (4)

    Object Number: 527362 Size: SH
  10. Disconnect the following electrical connectors:
    11. • The manifold absolute pressure (MAP) sensor (4)
    • The EVAP canister purge solenoid valve (1)

    Object Number: 363396 Size: SH
  11. Remove the engine wiring harness bracket from the stud at the EVAP canister purge solenoid valve.
  12. Move and secure the engine wiring harness out of the way.
  13. Remove the EVAP canister purge solenoid. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement in Engine Controls.

    14. Object Number: 528458 Size: SH
  14. Disconnect the vacuum hose from the intake manifold.

    15. Object Number: 527356 Size: SH
  15. Remove the bolt holding the transmission fluid filler tube to the accelerator control cable bracket.

    16. Object Number: 398027 Size: SH
  16. Remove the accelerator control cable bracket from the throttle body and the intake manifold.
  17. Remove the fuel lines from the fuel meter body assembly. Refer to Fuel Hose/Pipes Replacement - Engine Compartment in Engine Controls.

    18. Object Number: 516794 Size: SH
  18. Remove the studs for the upper intake manifold.
  19. Remove the upper intake manifold.

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

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

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

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

    Object Number: 516804 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 .
  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: 516804 Size: SH
  1. Install the throttle body, if removed. Refer to Throttle Body Assembly Replacement .
  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: 516773 Size: SH
  4. Install a NEW seal on the fuel meter body assembly.
  5. Lubricate the seal with clean engine oil.

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

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

    9. 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.

  9. Install the upper intake manifold attaching studs.

    10. 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).
  10. Install the fuel lines to the fuel meter body assembly. Refer to Fuel Hose/Pipes Replacement - Engine Compartment in Engine Controls.
  11. Install the EVAP canister purge solenoid valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement in Engine Controls.

    12. Object Number: 398027 Size: SH
  12. Install the accelerator control cable bracket, studs, and nuts to the intake manifold and the throttle body.

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


    Object Number: 528458 Size: SH
  13. Connect the vacuum hose to the intake manifold.

    14. Object Number: 527356 Size: SH
  14. Install the transmission fluid fill tube and bolt to the accelerator control cable bracket.

    15. Tighten
    Tighten the transmission fluid fill tube bolt 6 N·m (53 lb in).


    Object Number: 527368 Size: SH
  15. Position the engine wiring harness.
  16. Connect the following electrical connectors:
    17. • The A/C compressor clutch, if equipped (1)
    • The A/C high pressure cutoff switch, if equipped (5)
    • The throttle position (TP) sensor (2)
    • The idle air control (IAC) motor (3)
    • The fuel meter body assembly connector (4)

    Object Number: 527362 Size: SH
  17. Connect the following electrical connectors:
    18. • The manifold absolute pressure (MAP) sensor (4)
    • The EVAP canister purge solenoid valve (1)
  18. Install the engine wiring harness bracket and nut to the intake manifold stud.

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


    Object Number: 363396 Size: SH
  19. Install the engine wiring harness bracket and the nut onto the stud at the EVAP canister purge solenoid valve.

    20. Tighten
    Tighten the engine wiring harness bracket nut to 8 N·m (71 lb in).


    Object Number: 172995 Size: SH
  20. Connect the PCV valve hose assembly to the intake manifold and the valve rocker arm cover.
  21. 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.
  22. Install the accelerator control cable to the throttle shaft and the accelerator control cable bracket. Refer to Accelerator Control Cable Replacement in Engine Controls.
  23. Install the A/C compressor hose assembly. Refer to Auxiliary Air Conditioning Compressor and Condenser Hose Replacement .
  24. Install the air cleaner outlet duct to the throttle body assembly. Refer to Air Cleaner Outlet Duct Replacement in Engine Controls.
  25. Install the engine cover. Refer to Engine Cover Replacement in Interior Trim.

Intake Manifold Replacement Lower

Removal Procedure
  1. Disconnect the battery negative cable. Refer to Battery Replacement in Engine Electrical.
  2. Remove the engine cover. Refer to Engine Cover Replacement in Interior Trim.
  3. Drain the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
  4. Remove the air cleaner assembly. Refer to Air Cleaner Assembly Replacement in Engine Controls.
  5. Remove the air cleaner outlet duct from the throttle body assembly. Refer to Air Cleaner Outlet Duct Replacement in Engine Controls.
  6. Disconnect the accelerator control cable from the throttle shaft and the accelerator control cable bracket. Refer to Accelerator Control Cable Replacement in Engine Controls.
  7. Disconnect the cruise control cable, if equipped from the throttle shaft and the accelerator control cable bracket. Refer to Cruise Control Cable Replacement in Cruise Control.

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

    9. Object Number: 363391 Size: SH
  9. Remove the nut holding the A/C hose bracket to the intake manifold stud, if equipped.
  10. Remove the nut holding the engine wiring harness bracket to the intake manifold stud.

    11. Object Number: 527368 Size: SH
  11. Disconnect the following electrical connectors:
    12. • The A/C compressor clutch, if equipped (1)
    • The A/C high pressure cutoff switch, if equipped (5)
    • The throttle position (TP) sensor (2)
    • The idle air control (IAC) motor (3)
    • The fuel meter body assembly connector (4)

    Object Number: 527362 Size: SH
  12. Disconnect the following electrical connectors:
    13. • The manifold absolute pressure (MAP) sensor (4)
    • The EVAP canister purge solenoid valve (1)

    Object Number: 527361 Size: SH
  13. Disconnect the EGR valve electrical connector (1).
  14. Remove the ground wire (2) from the stud at the water outlet.

    15. Object Number: 363396 Size: SH
  15. Remove the nut and the engine wiring harness bracket from the stud at the EVAP canister purge solenoid valve.
  16. Move and secure the engine wire harness out of the way.
  17. Remove the EVAP canister purge solenoid valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement in Engine Controls.

    18. Object Number: 71614 Size: SH
  18. Remove the radiator inlet hose at the water outlet. Refer to Radiator Hose Replacement in Engine Cooling.
  19. Remove the heater hose from the intake manifold. Refer to Heater Water Bypass Valve Replacement in Heating Ventilation and Air Conditioning.
  20. Remove the water pump inlet hose from the intake manifold.

    21. Object Number: 528458 Size: SH
  21. Disconnect the vacuum hose from the intake manifold.

    22. Object Number: 527356 Size: SH
  22. Remove the bolt holding the transmission fluid filler tube to the accelerator control cable bracket.

    23. Object Number: 398027 Size: SH
  23. Remove the accelerator control cable bracket from the throttle body and the intake manifold.
  24. Remove the distributor. Refer to Distributor Replacement in Engine Electrical.
  25. Disconnect the fuel supply and the return pipes at the rear of the intake manifold. Refer to Fuel Hose/Pipes Replacement - Engine Compartment in Engine Controls.
  26. Remove the ignition control module (ICM). Refer to Ignition Coil and Ignition Coil Module Replacement in Engine Electrical.
  27. Remove the exhaust gas recirculation (EGR) valve inlet pipe from the intake and the exhaust manifolds. Refer to Exhaust Gas Recirculation Pipe Replacement in Engine Controls.

    28. Object Number: 340090 Size: SH
  28. In order to remove the front intake manifold bolt, perform the following:
    29. 28.1. Remove the drive belt. Refer to Drive Belt Replacement .
    28.2. Remove the A/C compressor side brace.
    28.3. Loosen the nut for the power steering pump rear bracket.
    28.4. Remove the oil filler tube bracket bolt and the oil filler tube.
    28.5. Remove the bolts and the nut for the power steering pump mounting bracket.
    28.6. Leave the A/C compressor, if equipped, and the power steering pump on the bracket.
    28.7. Slide the power steering pump bracket forward to access the bolt at the front of the intake manifold.
  29. Remove the lower intake manifold. Refer to Intake Manifold Removal .
  30. Clean all sealing surfaces and the intake manifold. Refer to Intake Manifold Cleaning and Inspection .
  31. 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. Reposition the power steering pump mounting bracket.

    3. 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.

  3. Install the power steering pump mounting bracket three bolts and the nut.

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

  4. Install A/C compressor side brace and bolts.

    5. Tighten

    1. Tighten the A/C compressor side brace bolt to 50 N·m (37 lb ft)
    2. Tighten the side brace bolt to the generator bracket to 25 N·m (18 lb ft).
  5. Install the oil filler tube and bolt.

    6. Tighten
    Tighten the oil filler tube bolt to 25 N·m (18 lb ft).

  6. Install the drive belt. Refer to Drive Belt Replacement .
  7. Install the exhaust gas recirculation (EGR) valve inlet pipe to the intake and the exhaust manifolds. Refer to Exhaust Gas Recirculation Pipe Replacement in Engine Controls.
  8. Install the EVAP canister purge solenoid valve. Refer to Evaporative Emission Canister Purge Solenoid Valve Replacement in Engine Controls.
  9. 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.

    10. 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.

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

    16. Object Number: 398027 Size: SH
  16. Install the accelerator control cable bracket, studs, and nuts to the intake manifold and the throttle body.

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


    Object Number: 528458 Size: SH
  17. Install the vacuum hose to the intake manifold.

    18. Object Number: 527356 Size: SH
  18. Install the transmission fluid fill tube and bolt to the accelerator control cable bracket.

    19. Tighten
    Tighten the transmission fluid fill tube bolt 6 N·m (53 lb in).


    Object Number: 71614 Size: SH
  19. Install the water pump inlet hose to the intake manifold.
  20. Install the heater hoses. Refer to Heater Water Bypass Valve Replacement in Heating Ventilation and Air Conditioning.
  21. Install the radiator inlet hose to the water outlet. Refer to Radiator Hose Replacement in Engine Cooling.

    22. Object Number: 527368 Size: SH
  22. Position the engine wiring harness.
  23. Connect the following electrical connectors:
    24. • The A/C compressor clutch, if equipped (1)
    • The A/C high pressure cutoff switch, if equipped (5)
    • The throttle position (TP) sensor (2)
    • The idle air control (IAC) motor (3)
    • The fuel meter body assembly connector (4)

    Object Number: 527362 Size: SH
  24. Connect the following electrical connectors:
    25. • The manifold absolute pressure (MAP) sensor (4)
    • The EVAP canister purge solenoid valve (1)

    Object Number: 527361 Size: SH
  25. Connect the EGR valve electrical connector (1).
  26. Install the ground wire (2) and the nut to the water outlet stud.

    27. Tighten
    Tighten the ground wire nut to 19 N·m (14 lb ft).


    Object Number: 363396 Size: SH
  27. Install the nut and the engine wiring harness bracket to the stud for the EVAP canister purge solenoid valve.

    28. Tighten
    Tighten the engine wiring harness bracket nut to 8 N·m (71 lb in).


    Object Number: 363391 Size: SH
  28. Install the nut and the engine wiring harness bracket to the intake manifold stud.

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

  29. Install the nut and the A/C hose bracket to the intake manifold stud, if equipped.

    30. Tighten
    Tighten the A/C hose bracket nut to 5 N·m (44 lb in).


    Object Number: 172995 Size: SH
  30. Install the PCV valve hose assembly to the intake manifold and the valve rocker arm cover.
  31. 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.
  32. Install the accelerator control cable to the throttle shaft and the accelerator control cable bracket. Refer to Accelerator Control Cable Replacement in Engine Controls.
  33. Refill the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
  34. Install air cleaner outlet duct to the throttle body. Refer to Air Cleaner Outlet Duct Replacement in Engine Controls.
  35. Install the air cleaner assembly. Refer to Air Cleaner Assembly Replacement in Engine Controls.
  36. Connect the battery negative cable. Refer to Battery Replacement in Engine Electrical.
  37. Install the engine cover. Refer to Engine Cover Replacement in Interior Trim.