GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2009 🢒 Lucerne 🢒 Engine 🢒 Engine Mechanical - 4.6L 🢒 Exhaust Manifold Cleaning and Inspection - Left Side

Cleaning Procedure
  1. Clean the exhaust manifold in solvent.

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

  2. Dry the exhaust manifold with compressed air.

Inspection Procedure

    Object Number: 578651 Size: SH
  1. Inspect the exhaust manifold for the following:
    2. • Damage to the exhaust crossover sealing area (1)
    • Damage or restrictions within the exhaust passages (2)
    • Damage to the gasket sealing surfaces (3)

    Object Number: 578660 Size: SH
  2. Inspect the exhaust manifold for the following:
    3. • Damage to the exhaust manifold mounting holes (1)
    • Damage or broken welds (2)
    • Damage or excessive corrosion to the exhaust manifold exterior (3)
    • Damage to the oxygen sensor threaded hole (4)
  3. Repair or replace the exhaust manifold and/or components as necessary.

    4. Object Number: 578675 Size: SH
  4. Measure the alignment or surface flatness of the exhaust manifold flanges, using a straight edge and a feeler gage. Exhaust manifold surface flatness must not exceed 0.254 mm (0.010 in).
  5. If the surface flatness is not within specifications, the exhaust manifold is warped and must be replaced.