Exhaust Manifold Cleaning and Inspection

CAUTION: Refer to SAFETY GLASSES CAUTION in Cautions and Notices.

Clean the exhaust manifolds in cleaning solvent.
Dry the components with compressed air.
Inspect the exhaust manifolds for the following:
- Damage to the gasket sealing surfaces (1)
- Damage to the exhaust gas recirculation (EGR) pipe fitting (2), left manifold
- Damage to the threaded holes (3)
- Restrictions within exhaust passages
- Broken or damaged exhaust manifold heat shields (4), if applicable
- Broken or damaged exhaust manifold
Fig 1: Exhaust Manifold Inspection Areas
Courtesy of GENERAL MOTORS CORP.
Measure the alignment or surface flatness of the exhaust manifold flanges using a straight edge and a feeler gage. Refer to Engine Mechanical Specifications .
If the surface flatness is not within the specifications, the exhaust manifold is warped and must be replaced.

Fig 2: Measuring Exhaust Manifold Flanges Alignment Or Surface Flatness
Courtesy of GENERAL MOTORS CORP.