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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1999 🢒 Chevy C Silverado - 2WD 🢒 General Information 🢒 General Information 🢒 Exhaust Manifold Installation

Exhaust Manifold Installation Left Side


    Object Number: 260074 Size: SH

    Important: 

       • Tighten the NEW exhaust manifold bolts as specified in the service procedure. Improperly installed and/or leaking exhaust manifold gaskets may affect vehicle emissions and/or on-board diagnostic (OBD) II system performance.
       • The cylinder head exhaust manifold bolt hole threads must be clean and free of debris or threadlocking material.
       • Do not apply sealant to the first 3 threads of the bolt.

  1. Apply a 5 mm (0.2 in) wide band of threadlock GM P/N 12345493 or equivalent to the threads of the NEW exhaust manifold bolts. Refer to Adhesives, Fluids, Lubricants, and Sealers .
  2. Install the exhaust manifold and NEW exhaust manifold gasket.

    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 NEW exhaust manifold bolts.

    4. Tighten

    1. Tighten the exhaust manifold bolts a first pass to 15 N·m (11 lb ft). Tighten the exhaust manifold bolts beginning with the center 2 bolts. Alternate from side-to-side, and work toward the outside bolts.
    2. Tighten the exhaust manifold bolts a final pass to 20 N·m (15 lb ft). Tighten the exhaust manifold bolts beginning with the center 2 bolts. Alternate from side-to-side, and work toward the outside bolts.
  4. Using a flat punch, bend over the exposed edge of the exhaust manifold gasket at the rear of the left cylinder head.

    5. Object Number: 492766 Size: SH
  5. Install the heat shield (2) and bolts (3).

    6. Tighten
    Tighten the heat shield bolts to 9 N·m (80 lb in).


    Object Number: 260103 Size: SH
  6. Install the air injection reaction (AIR) pipe studs (if required).

    7. Tighten
    Tighten the studs to 5 N·m (45 lb in).

  7. Install the AIR pipe (with check valve), NEW gasket, and nuts (if required).

    8. Tighten
    Tighten the AIR pipe to exhaust manifold nuts to 25 N·m (18 lb ft).

Exhaust Manifold Installation Right Side


    Object Number: 260093 Size: SH

    Important: 

       • Tighten the NEW exhaust manifold bolts as specified in the service procedure. Improperly installed and/or leaking exhaust manifold gaskets may affect vehicle emissions and/or on-board diagnostic (OBD) II system performance.
       • The cylinder head exhaust manifold bolt hole threads must be clean and free of debris or threadlocking material.
       • Do not reuse exhaust gas recirculation (EGR) valve and pipe gaskets or seals during assembly. Install NEW gaskets and O-ring seal.

  1. Apply a 5 mm (0.2 in) wide band of threadlock GM P/N 12345493 or equivalent to the threads of the NEW exhaust manifold bolts. Refer to Adhesives, Fluids, Lubricants, and Sealers .
  2. Install the exhaust manifold gasket and exhaust manifold.

    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 NEW exhaust manifold bolts.

    4. Tighten

    1. Tighten the exhaust manifold bolts a first pass to 15 N·m (11 lb ft). Tighten the exhaust manifold bolts beginning with the center 2 bolts. Alternate from side-to-side, and work toward the outside bolts.
    2. Tighten the exhaust manifold bolts a final pass to 20 N·m (15 lb ft). Tighten the exhaust manifold bolts beginning with the center 2 bolts. Alternate from side-to-side, and work toward the outside bolts.
  4. Using a flat punch, bend over the exposed edge of the exhaust manifold gasket at the front of the right cylinder head.

    5. Object Number: 492768 Size: SH
  5. Install the heat shield (2) and bolts (3).

    6. Tighten
    Tighten the heat shield bolts to 9 N·m (80 lb in).


    Object Number: 260104 Size: SH
  6. Install the air injection reaction (AIR) pipe studs (if required).

    7. Tighten
    Tighten the studs to 5 N·m (45 lb in).

  7. Install the AIR pipe (with check valve), NEW gasket, and nuts (if required).

    8. Tighten
    Tighten the AIR pipe to exhaust manifold nuts to 25 N·m (18 lb ft).


    Object Number: 260106 Size: SH
  8. Install the AIR hose assembly and clamps.

    9. Object Number: 260102 Size: SH
  9. Install the AIR pipe bracket-to-cylinder head bolt.

    10. Tighten
    Tighten the AIR pipe bracket bolt to 50 N·m (37 lb ft).


    Object Number: 260095 Size: SH
  10. Apply a light coating of clean engine oil to a NEW O-ring seal (1) and install the seal onto the EGR pipe (2).
  11. Insert the EGR pipe into the intake manifold.

    12. Object Number: 492762 Size: SH
  12. Start the EGR pipe to intake manifold bolt (1).

    13. Do not tighten the bolt at this time.

  13. Install the EGR pipe to cylinder head bolts.

    14. Do not tighten the bolts at this time.


    Object Number: 492764 Size: SH
  14. Install a NEW EGR pipe exhaust manifold gasket and bolts (1).

    15. Tighten

    1. Tighten the EGR pipe to intake manifold bolt to 10 N·m (89 lb in).
    2. Tighten the EGR pipe to cylinder head bolts to 50 N·m (37 lb ft).
    3. Tighten the EGR pipe to exhaust manifold bolts to 30 N·m (22 lb ft).

    Object Number: 260097 Size: SH
  15. Install the EGR valve, a NEW gasket, and bolts.

    16. Tighten

    1. Tighten the EGR valve bolts a first pass to 10 N·m (89 lb in).
    2. Tighten the EGR valve bolts a second pass to 25 N·m (18 lb ft).