GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 Yukon - 2WD 🢒 Engine 🢒 Engine Mechanical - 4.8L, 5.3L, and 6.0L 🢒 Exhaust Manifold Cleaning and Inspection

    Object Number: 492766 Size: SH

    Important: Do not reuse the exhaust manifold-to-cylinder head gaskets. Upon installation of the exhaust manifold, install a NEW gasket. A improperly installed gasket or leaking exhaust system may effect On-Board Diagnostics (OBD) II system performance.

  1. Clean the exhaust manifold (1) and heat shield (2) in solvent.
  2. Dry the exhaust manifold with compressed air.
  3. Inspect the exhaust manifold Air Injection Reaction (AIR) passages for restrictions (if applicable).
  4. Inspect the AIR flange studs and threaded bolt holes for damage.
  5. Inspect the AIR flange gasket surface for excessive scratches or gouging.
  6. Inspect the exhaust manifold-to-cylinder head gasket surface for excessive scratches or gouging.
  7. Inspect the right side manifold Exhaust Gas Recirculation (EGR) flange sealing surface for excessive scratches or gouging.
  8. Inspect the right side manifold EGR flange bolt hole threads for damage.
  9. Inspect for a loose or damaged heat shield (2).
  10. Inspect the take down studs for damaged threads.

    11. Object Number: 66607 Size: SH
  11. Use a straight edge and a feeler gauge and measure the exhaust manifold cylinder head deck for warpage.

    12. An exhaust manifold deck with warpage in excess of 0.25 mm (0.01 in) within the two front or two 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.