Exhaust Manifold Replacement - Left Side 4.8L, 5.3L, and 6.0L Engines

1. Remove the ignition coils. Refer to Ignition Coil Replacement in Engine Controls - 4.8L, 5.3L, and 6.0L.
2. Remove the spark plugs. Refer to Spark Plug Replacement in Engine Controls - 4.8L, 5.3L, and 6.0L.
3. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
4. Remove the exhaust manifold pipe nuts.
5. Lower the vehicle.



6. Remove the exhaust manifold bolts, manifold, and gasket.
7. Discard the gasket.



8. Remove the heat shield bolts (3), and shield (2) from the exhaust manifold (1), if necessary.
9. Clean and inspect the exhaust manifold, if the manifold is not being replaced. Refer to Exhaust Manifold Cleaning and Inspection in Engine Mechanical - 4.8L, 5.3L, and 6.0L.

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.

1. Install the heat shield (2), and bolts (3) to the exhaust manifold (1), if necessary.

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





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.

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

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

Tighten

1. Tighten the bolts a first pass to 15 N·m (11 lb ft). Tighten the exhaust manifold 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 exhaust manifold bolts beginning with the center two 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. Raise the vehicle.



6. Install the exhaust manifold pipe nuts.

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

7. Lower the vehicle.
8. Install the spark plugs. Refer to Spark Plug Replacement in Engine Controls - 4.8L, 5.3L, and 6.0L.
9. Install the ignition coils. Refer to Ignition Coil Replacement in Engine Controls - 4.8L, 5.3L, and 6.0L.

Exhaust Manifold Replacement - Left Side 8.1L Engine

1. Remove the wheelhouse panel. Refer to Wheelhouse Panel Replacement in Body Front End.

Important: Twist the spark plug boot one-half turn in order to release the boot. Pull on the spark plug boot only. Do not pull on the spark plug wire or the wire could be damaged.

2. Remove the spark plug wires from the spark plugs and ignition coils.
3. Remove the spark plugs. Refer to Spark Plug Replacement in Engine Controls - 8.1L.
4. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.



5. Remove the exhaust manifold heat shield bolts and nuts.
6. Remove the exhaust manifold heat shield.
7. Lower the vehicle.



8. Remove the exhaust manifold bolt and nuts.
9. Remove the exhaust manifold.
10. Remove and discard the exhaust manifold gasket.
11. Clean and inspect the exhaust manifold, if the manifold is not being replaced. Refer to Exhaust Manifold Cleaning and Inspection in Engine Mechanical - 8.1L.

1. Install a NEW exhaust manifold gasket.
2. Install the exhaust manifold.

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 bolt and nuts.

Tighten

•	Tighten the bolt to 35 N·m (26 lb ft).

•	Tighten the nuts to 16 N·m (12 lb ft).

4. Raise the vehicle.



5. Install the exhaust manifold heat shield.
6. Install the exhaust manifold heat shield bolts and nuts.

Tighten
Tighten the bolts and nuts to 25 N·m (18 lb ft).

7. Lower the vehicle.
8. Install the spark plugs. Refer to Spark Plug Replacement in Engine Controls - 8.1L.




Important: Fully install the spark plug wire by pushing on the exposed end of the spark plug boot. Do not push the spark plug wire on to the spark plug by using the metal heat shield.

9. Install the spark plug wires to the spark plugs and ignition coils.
10. Install the wheelhouse panel. Refer to Wheelhouse Panel Replacement in Body Front End.