Exhaust Manifold Cleaning and Inspection
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2012 GMC Yukon XL, 2012 GMC Yukon, 2012 Chevrolet Tahoe, 2012 Chevrolet Suburban, and 2012 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
- Clean the exhaust manifold (600) and heat shield (603) in solvent.
- Dry the exhaust manifold with compressed air.
- Inspect the exhaust manifold-to-cylinder head gasket surface for excessive scratches or gouging.
- Inspect for a loose, damaged, or cracked heat shield (603).
- Inspect the studs (605) for damaged threads.
- Use a straight edge and a feeler gauge 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 2 front or 2 rear runners or 0.5 mm (0.02 in) overall, may cause an exhaust leak and may affect OBD II system performance. Exhaust manifolds not within specifications must be replaced.
NOTE:
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 affect on-board diagnostics (OBD) II system performance.
WARNING:
Refer to Safety Glasses Warning .