57. Exhaust Manifold Cleaning and Inspection

Exhaust Manifold Cleaning and Inspection


Important: Do not use the exhaust manifold-to-cylinder head gaskets again. Upon installation of the exhaust manifold, install a NEW gasket. An incorrectly installed gasket or leaking exhaust system may effect on-board diagnostics (OBD) II system performance.


1. Clean the exhaust manifold and heat shield in solvent.
Caution: Refer to Safety Glasses Caution (Safety Glasses Warning) .
2. Dry the exhaust manifold with compressed air.
3. Visually inspect the exhaust manifolds for the following conditions:

* Damage to the gasket sealing surfaces.
* Distortion of exhaust manifold mating surface.
* Damage to the exhaust mounting holes.





4. Check for distortion on the mating surface of the exhaust manifold (3) by using a straight edge (1) and a feeler gauge (2).
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 effect OBD II system performance. Exhaust manifolds not within specifications must be replaced.