For 1990-2009 cars

1. Clean the exhaust manifolds in solvent.

Caution: Refer to Safety Glasses Caution in the Preface section.

2. Dry the exhaust manifolds with compressed air.
3. Inspect the exhaust manifolds for the following conditions:

• | 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

4. 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).
5. If the surface flatness is not within specifications, the exhaust manifold is warped and must be replaced.