Exhaust Manifold Cleaning and Inspection (LDK, LHU)

WARNING: This page is about a different variant/trim than selected.

Fig 1: Exhaust Manifold

Courtesy of GENERAL MOTORS COMPANY

NOTE:

Do not reuse the exhaust manifold-to-cylinder head gaskets. 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.

Clean the exhaust manifold in solvent.

WARNING:

Refer to Safety Glasses Warning .

Dry the exhaust manifold (1) with compressed air.
Inspect the heat shield for damage.

Fig 2: Inspecting Turbocharger Inlet Mating Surfaces For Damage

Courtesy of GENERAL MOTORS COMPANY

NOTE:

Do not replace the exhaust manifold if cracks are found on the manifold outlet flange partition wall (1). Replacement should only be performed if external leaks are present.

Internal heat cracks are allowed. Do not replace the exhaust manifold for this condition.

Fig 3: Inspecting Exhaust Manifold For Flatness

Courtesy of GENERAL MOTORS COMPANY

Use a straight edge (2) and a feeler gauge (1) and measure the exhaust manifold mounting face for warpage.
An exhaust manifold face with warpage in excess of 0.25 mm (0.0100 in) may cause an exhaust leak and may affect OBD II system performance. Exhaust manifolds not within specifications must be replaced.