Exhaust Manifold Cleaning and Inspection

WARNING: This page is about a different variant/trim than selected.

Clean the exhaust manifold (1) in solvent.

Fig 1: Exhaust Manifold
Courtesy of GENERAL MOTORS COMPANY

NOTE: Do not reuse the exhaust manifold-to-cylinder head gaskets. 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. Remove the oxygen sensor prior to cleaning the manifold. Do not submerge the oxygen sensor in cleaning solvent.
Dry the exhaust manifold with compressed air.
WARNING: Refer to Safety Glasses and Compressed Air Warning .
Inspect the heat shield for damage.
Use a straight edge and a feeler gauge and measure the exhaust manifold mounting face for warpage.

Fig 2: Checking Exhaust Manifold Mounting Face For Warpage
Courtesy of GENERAL MOTORS COMPANY

An exhaust manifold face with warpage in excess of 0.25 mm (0.0100 in) may cause an exhaust leak and may effect OBD II system performance. Exhaust manifolds not within specifications must be replaced.