Exhaust Manifold Replacement - Right Side LS4

1. Remove the engine sight shield. Refer to Upper Intake Manifold Sight Shield Replacement.
2. Remove the spark plugs. Refer to Spark Plug Replacement.
3. Remove the exhaust crossover pipe nuts from the right exhaust manifold.
4. Disconnect the catalytic converter from the exhaust manifold. Refer to Catalytic Converter Replacement.
5. Support the catalytic convertor and exhaust system with the mechanics wire.
6. Lower the vehicle.
7. Remove the ignition coil. Refer to Ignition Coil Replacement.
8. Remove the heated oxygen sensor (HO2S). Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1.



9. Remove the exhaust manifold heat shield bolts (604).
10. Remove the exhaust manifold heat shield (603).



11. Remove the exhaust manifold bolts.
12. Remove the exhaust manifold.
13. Remove and discard the exhaust manifold gasket.

Note: 

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.

Caution: Refer to Fastener Caution in the Preface section.

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

Tighten

•	Tighten the bolts a first pass to 15 N·m (11 lb ft). Tighten the bolts beginning with the center 2 bolts. Alternate from side to side, and work toward the outside.

•	Tighten the bolts a final pass to 20 N·m (15 lb ft). Tighten the bolts beginning with the center 2 bolts. Alternate from side to side, and work toward the outside.

3. Using a flat punch, bend over the exposed edge of the exhaust manifold gasket at the rear of the right cylinder head.



4. Install the exhaust manifold heat shield (603).
5. Install the exhaust manifold heat shield bolts (604).

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

6. Install the O2 sensor. Refer to Spark Plug Replacement.
7. Raise the vehicle.
8. Remove the mechanics wire from the exhaust system and connect the catalytic converter. Refer to Catalytic Converter Replacement.



9. Install the exhaust crossover pipe nuts to the right exhaust manifold.

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

10. Install the ignition coil. Refer to Ignition Coil Replacement.
11. Install the spark plugs. Refer to Spark Plug Replacement.
12. Install the fuel injector sight shield. Refer to Upper Intake Manifold Sight Shield Replacement.

Exhaust Manifold Replacement - Right Side LZE/LZ4/LZ8

Special Tools

J 39194-B Heated Oxygen Sensor Socket

1. Remove the generator. Refer to Generator Replacement.
2. Remove the connector position assurance (CPA) retainer (3).
3. Disconnect the heated oxygen sensor (HO2S) electrical connector (2).
4. Remove the HO2S clip (1) from the ignition coil bracket.




Note: The HO2S uses a permanently attached pigtail and connector. This pigtail should not be removed from the sensor. Damage or removal of the pigtail or connector will affect proper operation of the sensor.

5. Remove the HO2S using the J 39194-B .



6. Remove the exhaust manifold shield bolts.
7. Remove the exhaust manifold shield.



8. Remove the exhaust crossover pipe heat shield bolts.
9. Remove the exhaust crossover pipe heat shield.



10. Remove the exhaust crossover pipe to right exhaust manifold nuts.



11. Remove the upper exhaust manifold bolts.
12. Remove the catalytic converter. Refer to Catalytic Converter Replacement.
13. Remove the lower exhaust manifold bolts.
14. Remove the exhaust manifold.
15. Remove and discard the exhaust manifold gasket.

1. Install a NEW exhaust manifold gasket onto the cylinder head studs.
2. Install the exhaust manifold.

Caution: Refer to Fastener Caution in the Preface section.

3. Install the lower exhaust manifold bolts.

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

4. Install the catalytic converter. Refer to Catalytic Converter Replacement.
5. Lower the vehicle.
6. Install the upper exhaust manifold bolts.

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




7. Install the exhaust crossover pipe to right exhaust manifold nuts.



8. Install the exhaust crossover pipe heat shield.
9. Install the exhaust crossover pipe heat shield bolts.



10. Install the exhaust manifold shield.
11. Install the exhaust manifold shield bolts.

Tighten
Tighten the bolts to 10 N·m (89 lb in).





Note: Whenever the oxygen sensor is removed, coat the threads with nickel-based anti-seize compound such as GM P/N 5613695 (or equivalent).

12. Install the HO2S using J 39194-B .

Tighten
Tighten the sensor to 42 N·m (31 lb ft).




13. Connect the HO2S electrical connector (2).
14. Install the CPA retainer (3).
15. Install the HO2S clip (1) to the ignition coil bracket.
16. Install the generator. Refer to Generator Replacement.