Inspection Procedure

Courtesy of GENERAL MOTORS COMPANY

Inspect the charge air cooler for the following conditions:

• Damage to the charge air cooler bolt holes (1)
• Damage, debris or restrictions to the intake manifold purge fitting (2)
• Damage to the Intake air pressure and temperature sensor holes (3)
• Damage to the charge air cooler inlet air tube sealing surface (4)
• Damage to the turbocharger water manifold sealing surface (5)

Fig 1: Identifying Lower Intake Manifold Inspection Points (LF4)

Courtesy of GENERAL MOTORS COMPANY

Inspect the lower intake manifold for the following conditions:

• Damage, debris or restrictions to the throttle actuator wire assembly hole (1)
• Damage, debris or restrictions to the charge air cooler cover seal bosses (2)
• Damage to the throttle body sealing surface (3)
• Gouges or damage to the intake manifold sealing surfaces (4)
• Damage to the intake manifold tube (5)
• Damage, debris or restrictions to the MAP sensor hole (6)
• Damage, debris or restrictions to the charge air cooler lower insulators (7)
• Damage to the intake manifold vacuum fitting (8)
• Damage to the PCV tube fitting (9)
• Damage to the intake manifold vacuum fitting (10)

1. Locate a straight edge across the lower intake manifold sealing surface.
2. Insert a feeler gauge between the lower intake manifold and the straight edge. An lower intake manifold with warpage in excess of 0.50 mm (0.020 in) must be replaced.