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For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2003 🢒 Envoy - 2WD 🢒 Engine 🢒 Engine Electrical 🢒 Exhaust Manifold Replacement - Left Side

Exhaust Manifold Replacement - Left Side 5.3L Engine

Removal Procedure

    Object Number: 899634 Size: SH
  1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  2. Remove the exhaust manifold pipe nuts.
  3. Lower the vehicle.
  4. Remove the spark plugs. Refer to Spark Plug Replacement in Engine Controls - 4.8L, 5.3L, and 6.0L.

    5. Object Number: 899631 Size: SH
  5. Remove the heat shield bolts, and shield from the exhaust manifold.
  6. Remove the exhaust manifold bolts, manifold, and gasket.
  7. Discard the gasket.
  8. Clean and inspect the exhaust manifold. Refer to Exhaust Manifold Cleaning and Inspection .

Installation Procedure

Important: 

   • Tighten the 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 Diagnostics (OBD) II system performance.
   • The cylinder head exhaust manifold bolt hole threads must be clean and free of debris or threadlocking material.

Important: Do not apply sealant to the first three threads of the bolt.


    Object Number: 899631 Size: SH
  1. Apply a 5 mm (0.2 in) wide band of threadlock GM P/N 12345493, (Canadian P/N 10953488), or equivalent to the threads of the exhaust manifold bolts.

    2. 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.

  2. Install the exhaust manifold, NEW gasket and bolts.

    3. Tighten

    1. Tighten the bolts a first pass to 15 N·m (11 lb ft). Tighten the bolts beginning with the center two bolts. Alternate from side-to-side, and work toward the outside bolts.
    2. Tighten the bolts a final pass to 25 N·m (18 lb ft). Tighten the bolts beginning with the center two bolts. Alternate from side-to-side, and work toward the outside bolts.
  3. Install the heat shield, and bolts to the exhaust manifold.

    4. Tighten
    Tighten the bolts to 9 N·m (80 lb in).

  4. Using a flat punch, bend over the exposed edge of the exhaust manifold gasket at the rear of the left cylinder head.
  5. Install the spark plugs. Refer to Spark Plug Replacement in Engine Controls - 4.8L, 5.3L, and 6.0L.
  6. Raise the vehicle.

    7. Object Number: 899634 Size: SH
  7. Install the exhaust manifold pipe nuts.

    8. Tighten
    Tighten the nuts to 50 N·m (37 lb ft).

  8. Lower the vehicle.