GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1999 🢒 Corvette 🢒 Engine 🢒 Engine Controls - 5.7L 🢒 Exhaust Manifold Cleaning and Inspection

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.
   • Remove the oxygen sensor prior to cleaning the manifold, do not submerge the oxygen sensor in cleaning solvent.

  1. Remove the oxygen sensor from the manifold.

    2. Object Number: 363589 Size: SH
  2. Clean the exhaust manifold in solvent.

    3. Caution: Wear safety glasses in order to avoid eye damage.

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

    11. Object Number: 64015 Size: SH
  11. Inspect the take down studs for damaged threads.

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

    13. A exhaust manifold deck with warpage in excess of 0.25 mm (0.01 in), may cause an exhaust leak and may effect (On-Board Diagnostic) OBD II system performance. Exhaust manifolds not within specifications must be replaced.