GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1998 🢒 Chevy P12 Chassis 🢒 Engine 🢒 Engine Mechanical - 7.4L 🢒 Exhaust Manifold Replacement

Removal Procedure

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  1. Disconnect the negative battery cable.
  2. Remove the oil level indicator and tube from the engine block. Refer to Oil Level Indicator and Tube Replacement .

    3. Object Number: 173284 Size: SH
  3. Remove the EGR valve pipe from the left exhaust manifold. Refer to Exhaust Gas Recirculation Pipe Replacement in Engine Controls.
  4. Remove the spark plugs from the cylinder head. Refer to Spark Plug Replacement in Engine Electrical.
  5. Remove the spark plug heat shield bolts and the heat shields.
  6. Remove the exhaust pipe from the exhaust manifold. Refer to Exhaust Pipe Replacement .

    7. Object Number: 276377 Size: SH
  7. Remove the exhaust manifold retaining nuts.
  8. Remove the exhaust manifold from the cylinder head.
  9. Remove the exhaust manifold gasket from the cylinder head.
  10. Clean and check the gasket mating surface and the cylinder head. Refer to Cylinder Head Cleaning and Inspection .

Installation Procedure

    Object Number: 180888 Size: SH

    Important: Install the exhaust manifold gasket with the stamped 7.4 facing away from the cylinder head.

  1. Install the exhaust manifold gasket to the cylinder head.

    2. Object Number: 276377 Size: SH
  2. Install the exhaust manifold to the cylinder head.

    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 exhaust manifold retaining nuts.

    4. Tighten
    Tighten the nuts to 30 N·m (22 lb ft).

    • Tighten the center bolt to 54 N·m (40 lb ft).

    Object Number: 65852 Size: SH
  4. Install the spark plug heat shields.

    5. Tighten
    Tighten the bolts to 20 N·m (15 lb ft).


    Object Number: 258830 Size: SH
  5. Install the oil level indicator tube to the exhaust manifold. Refer to Oil Level Indicator and Tube Replacement .
  6. Install the spark plugs to the cylinder head. Refer to Spark Plug Replacement in Engine Electrical.
  7. Install the exhaust pipes to the exhaust manifolds. Refer to Exhaust Pipe Replacement in Engine Exhaust.

    8. Object Number: 173284 Size: SH
  8. Install the EGR pipe to the intake manifold and the exhaust manifold. Refer to Exhaust Gas Recirculation Pipe Replacement in Engine Controls.

    9. Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  9. Connect the negative battery cable.