GM Service Manual Online
For 1990-2009 cars only

Intake Manifold Cleaning and Inspection Upper

Important: Do not reuse the upper intake manifold-to-lower intake manifold sealing gaskets.

  1. Remove and discard the upper intake manifold-to-lower intake manifold gaskets.

  2. Object Number: 18303  Size: SH
  3. Remove and discard the throttle body gasket.
  4. Clean the upper intake manifold in an approved solvent.
  5. • Clean the upper intake manifold gasket sealing surfaces.
    • Clean all engine coolant passages of scale build up.
    • Clean all carbon from the EGR passages.
    • Clean all upper intake manifold ports.
    • Inspect upper intake manifold sealing surfaces for nicks and cracks.

       Caution: Wear safety glasses in order to avoid eye damage.

    • Dry the upper intake manifold with compressed air.

Intake Manifold Cleaning and Inspection Lower

Important: Do not reuse the lower intake manifold-to-cylinder head sealing gaskets.

  1. Inspect the sealing grommet on the MAP sensor. The grommet should not be torn or damaged.
  2. Remove and discard the lower intake manifold-to-cylinder head gaskets.
  3. Clean the lower intake manifold in an approved solvent.
  4. • Clean the lower intake manifold gasket sealing surfaces.
    • Clean all engine coolant passages of scale build up.
    • Clean all carbon from the EGR passages.
    • Clean all lower intake manifold ports.
    • Inspect lower intake manifold sealing surfaces for nicks and cracks.

       Caution: Wear safety glasses in order to avoid eye damage.

    • Dry the lower intake manifold with compressed air.