Exhaust Manifold Cleaning and Inspection
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2003 GMC Savana Special, 2003 GMC Savana Camper Special, 2003 GMC Savana, 2003 Chevrolet RV Cutaway, and 2003 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
Important: Do not use the exhaust manifold-to-cylinder head gaskets again. 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.
- Clean the exhaust manifold (1) and heat shield (2) in solvent.
- Dry the exhaust manifold with compressed air.
- Inspect the exhaust manifold-to-cylinder head gasket surface for excessive scratches or gouging.
- Inspect the right side manifold exhaust gas recirculation (EGR) flange sealing surface for excessive scratches or gouging, if applicable.
- Inspect the right side manifold EGR flange bolt hole threads for damage.
- Inspect for a loose or damaged heat shield (2).
- Inspect the take down studs for damaged threads.
- Use a straight edge and a feeler gage and measure the exhaust manifold cylinder head deck for warpage.
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.