56. Exhaust Manifold Cleaning and Inspection

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 improperly installed gasket or leaking exhaust system may effect on-board diagnostics (OBD) II system performance.





1. Clean the exhaust manifold (600) and heat shield (603) in solvent.

Caution: Refer to Safety Glasses Caution in Service Precautions.

2. Dry the exhaust manifold with compressed air.
3. Inspect the exhaust manifold-to-cylinder head gasket surface for excessive scratches or gouging.
4. Inspect for a loose, damaged, or cracked heat shield (603).
5. Inspect the studs (605) for damaged threads.





6. 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 inch) within the two front or two rear runners or 0.5 mm (0.02 inch) overall, may cause an exhaust leak and may effect OBD II system performance. Exhaust manifolds not within specifications must be replaced.