Inspection Procedure

WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: View Of Upper Intake Manifold

Courtesy of GENERAL MOTORS CORP.

Inspect the upper intake manifold for the following conditions:
- Damage, debris or restrictions to the brake vacuum booster hose port
- Damage to the throttle body bolt holes
- Damage, debris or restrictions to the PCV system hose ports
- Damage to the gasket sealing surface for the intake manifold cover

Fig 2: View Of Upper Intake Manifold

Courtesy of GENERAL MOTORS CORP.

Inspect the upper intake manifold for the following conditions:
- Damage to the intake manifold bolt bosses
- Damage to the EVAP purge solenoid mounting boss
- Damage, debris or restrictions to the EVAP purge solenoid port
- Damage, debris or restrictions in the vacuum passage

Fig 3: View Of Upper Intake Manifold Sealing Surfaces

Courtesy of GENERAL MOTORS CORP.

Inspect the intake manifold for the following conditions:
- Gouges or damage to the intake manifold sealing surfaces
- Damage to the gasket sealing surface for the throttle body

Fig 4: Inspecting Upper Intake Manifold Sealing Surface For Warpage

Courtesy of GENERAL MOTORS CORP.

Inspect the upper intake manifold sealing surface for warpage.
1. Locate a straight edge across the intake manifold sealing surface.
2. Insert a feeler gage between the upper intake manifold and the straight edge. An intake manifold with warpage in excess of 0.50 mm (0.020 in) must be replaced.
Repair or replace the upper intake manifold as necessary.