For 1990-2009 cars

### 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. Disconnect the O2S (Oxygen) sensor connector.
3. Raise and support the vehicle. Refer to General Vehicle Lifting and Jacking.
4. Remove the exhaust manifold brace to manifold fasteners.
5. Remove the upper heat shield.

Notice: Do not bend the exhaust flex decoupler more than 3 degrees in any direction. Movement of more than 3 degrees will damage the exhaust flex decoupler.

6. Remove the manifold to the exhaust flex decoupler fasteners.
7. Pull down and back on the exhaust pipe to disengage it from the exhaust manifold.
8. Lower the vehicle.
9. Remove the exhaust manifold to cylinder head retaining nuts.
10. Remove the exhaust manifold, seals and gaskets.
11. Clean all sealing surfaces.

### Installation Procedure

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 nuts.

Tighten
Tighten the nuts to 13 N·m (110 lb in).

Raise and support the vehicle. Refer to General Vehicle Lifting and Jacking.

4. Install the heat shield.

Tighten
Tighten the bolts to 14 N·m (124 lb in).

5. Install the exhaust manifold brace to exhaust manifold fasteners.

Tighten

• | Tighten the bolt to 56 N·m (41 lb ft).

• | Tighten the nuts to 26 N·m (19 lb ft).

6. Install the manifold to the flex decoupler fasteners.

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

7. Lower the vehicle.
8. Coat the threads of the O2S (Oxygen sensor) connector with anti-seize compound GM P/N 5613695 or equivalent.
9. Connect the O2S (Oxygen sensor) connector.
10. Connect the negative battery cable.