Removal procedure
1. Disconnect the negative battery cable.
2. Remove the front exhaust pipe. See Part 1G3, Exhaust System - HFV6 3.2L.
3. Remove the auxiliary catalytic converter. See Part 1G3, Exhaust System - HFV6 3.2L.
4. Exhaust manifold bank 1: remove transfer case. See Part 5D. "Transfer case".
5. Exhaust manifold bank 1: Remove the rear suspension of the transmission with the final drive assembly. See "Rear suspension of the gearbox with the main gear assembly" in this section.
6. Disconnect the upper oxygen sensor connector.
7. Remove the three bolts (1) securing the outer heat-insulating shield (2) to the exhaust manifold.
8. Gradually loosen the seven exhaust manifold mounting bolts, working from the center to the outer bolts, and then remove the bolts.
9. Remove and discard the gasket between the exhaust manifold and the cylinder head.
10. Remove the three bolts securing the inner heat shield to the exhaust manifold, if required.
Clear
1. Thoroughly clean the exhaust manifold using any of the common non-corrosive cleaning solvents and a soft bristle brush.
2. Dry the exhaust manifold with compressed air.
Inspection
1. Inspect the exhaust manifold (1), checking for the following faults:
- Damage to threaded holes intended for fastening thermal insulation shields.
- Damage to the holes intended for mounting the exhaust manifold.
- Damage to the threads securing the exhaust manifold to the exhaust pipe flange studs.
- Damage to surfaces sealed by gaskets.
- Using a ruler (2) and feeler gauges (3), check the joint surface of the exhaust manifold with the cylinder head for deformation, which should not exceed 0.25 mm.
Note: If the surface flatness differs from the required level, the exhaust manifold is deformed and must be replaced.
Installation procedure
1. Install the exhaust manifold inner heat shield if required.
Tighten
Tighten the exhaust manifold inner heat shield bolts to 10 N·m (89 lb-ft).
2. Place the new exhaust manifold gasket onto the manifold.
3. Lubricate the threads of the exhaust manifold mounting bolts with Loctite 272 thread sealant (or equivalent).
Note: When tightening the exhaust manifold to cylinder head bolts, start with the center bolts and then move to the bolts on opposite sides one by one.
4. Install the exhaust manifold and mounting bolts.
Tighten
Tighten the exhaust manifold to cylinder head bolts to 20 N·m (15 lb-ft).
5. Install the exhaust manifold heat shield.
Tighten
Tighten the exhaust manifold outer heat shield bolts to 10 N·m (89 lb-ft).
6. Install previously removed external parts.
[The material was created based on information from the website: «ChevyMan»]