GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2008 🢒 G8 🢒 Engine 🢒 Engine Mechanical - 4.8L, 5.3L, 6.0L, 6.2L, or 7.0L 🢒 Exhaust Manifold Cleaning and Inspection

    Important: Do not use the exhaust manifold-to-cylinder head gaskets again. Upon installation of the exhaust manifold, install a NEW gasket. An incorrectly installed gasket or leaking exhaust system may effect on-board diagnostics (OBD)  II system performance.

  1. Clean the exhaust manifold and heat shield in solvent.

    2. Caution: Refer to Safety Glasses Caution in the Preface section.

  2. Dry the exhaust manifold with compressed air.
  3. Visually inspect the exhaust manifolds for the following conditions:
    4. • Damage to the gasket sealing surfaces.
    • Distortion of exhaust manifold mating surface.
    • Damage to the exhaust mounting holes.

    Object Number: 1954058 Size: SH
  4. Check for distortion on the mating surface of the exhaust manifold (3) by using a straight edge (1) and a feeler gauge (2).

    5. An exhaust manifold deck with warpage in excess of 0.25 mm (0.01 in) within the 2 front or 2 rear runners or 0.5 mm (0.02 in) overall, may cause an exhaust leak and may effect OBD II system performance. Exhaust manifolds not within specifications must be replaced.