For 1990-2009 cars

### Removal Procedure

1. Remove the coolant intake pipe. Refer to Engine Coolant Inlet Pipe Replacement in Engine Cooling.
2. Remove the 3 exhaust manifold lower heat shield bolts.
3. Remove the exhaust manifold lower heat shield.
4. Remove the 3 lower nuts on the rear of the exhaust manifold.
5. Remove the exhaust manifold upper rear heat shield bolt.
6. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
7. Remove the catalytic converter nuts from the exhaust manifold.
8. Lower the vehicle.
9. Remove the accessory drive belt tensioner. Refer to Drive Belt Tensioner Replacement .
10. Remove the 2 nuts on the front of the exhaust manifold.
11. Remove the exhaust manifold upper heat shield bolts. The upper heat shield stays in place. The bolts are removed to enable access to the AIR pipe.
12. Remove the AIR pipe bolts (1).
13. Remove the AIR pipe (2) from the exhaust manifold.
14. Remove the 2 upper nuts on the exhaust manifold.
15. Raise the vehicle.
16. Remove the exhaust manifold from under the vehicle.
17. Remove the exhaust manifold gasket.
18. Clean the exhaust manifold gasket mating surfaces.

### Installation Procedure

1. Install the exhaust manifold gasket.
2. Install the exhaust manifold.
3. Install the 2 upper nuts to 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.

4. Install the 2 upper nuts to the exhaust manifold.

Tighten
Tighten the exhaust manifold nuts to 20 N·m (15 lb ft).

5. Lower the vehicle.
6. Install the AIR pipe (2) to the exhaust manifold.
7. Coat the AIR pipe bolts (1) with high temperature anti-seize compound, GM P/N 12371386 or equivalent.
8. Install the AIR pipe bolts (1).

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

9. Coat the exhaust manifold upper heat shield bolts with high temperature anti-seize compound, GM P/N 12371386 or equivalent.
10. Install the exhaust manifold upper heat shield bolts.

Tighten
Tighten the exhaust manifold upper heat shield bolts to 8 N·m (71 lb in).

11. Install the 2 lower nuts to the front of the exhaust manifold.

Tighten
Tighten the exhaust manifold nuts to 20 N·m (15 lb ft).

12. Install the accessory drive belt tensioner. Refer to Drive Belt Tensioner Replacement .
13. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
14. Install the catalytic converter nuts to the exhaust manifold.

Tighten
Evenly tighten the catalytic converter nuts to 20 N·m (15 lb ft).

15. Lower the vehicle.
16. Coat the exhaust manifold upper rear heat shield bolt with high temperature anti-seize compound, GM P/N 12371386 or equivalent.
17. Install the exhaust manifold upper rear heat shield bolt.
18. Install the 3 lower nuts to the rear of the exhaust manifold.

Tighten
Tighten the exhaust manifold nuts to 20 N·m (15 lb ft).

19. Install the exhaust manifold lower heat shield.
20. Coat the exhaust manifold lower heat shield bolts with high temperature anti-seize compound, GM P/N 12371386 or equivalent.
21. Install the exhaust manifold lower heat shield bolts.

Tighten
Tighten the exhaust manifold lower heat shield bolts to 8 N·m (71 lb in).

22. Install the coolant intake pipe. Refer to Engine Coolant Inlet Pipe Replacement in Engine Cooling.