Exhaust Manifold Cleaning and Inspection

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Clean the exhaust manifolds in solvent.

Fig 1: View Of Left Exhaust Manifold, Gasket, Bolts And Nuts

Courtesy of GENERAL MOTORS CORP.

CAUTION: Refer to Safety Glasses Caution in Cautions and Notices.

Dry the components with compressed air.
Inspect the exhaust manifolds for the following:
- Damage to the gasket sealing surfaces
- Damage to the exhaust manifold studs
- Broken or damaged heat shields
- Cracks in the exhaust manifold
- Restrictions within the exhaust passages
Measure the alignment or surface flatness of the exhaust manifold flanges, using a straight edge and a feeler gage. Exhaust manifold surface flatness must not exceed 0.254 mm (0.01 in).

Fig 2: Measuring Exhaust Manifold To Cylinder Head Surface For Warpage

Courtesy of GENERAL MOTORS CORP.

If the surface flatness is not within specifications, the exhaust manifold is warped and must be replaced.