52. Intake Manifold Clean and Inspect
Cleaning ProcedureImportant: Do not reuse the intake manifold-to-cylinder head sealing gaskets.
1. Remove and discard the intake manifold-to-cylinder head gaskets.
2. Remove any remaining gasket and/or gasket material from the following:
- Throttle body
- Throttle body adapter heater plate
- Intake manifold
3. Clean the following intake manifold areas in solvent.
- Intake manifold gasket grooves
- Intake manifold passages
- Brake booster hose passage
- EVAP solenoid passage
- PCV vacuum hose passages
- MAP sensor passage
- Throttle body adapter heater plate
Caution: Wear safety glasses in order to avoid eye damage.
4. Dry the intake manifold and throttle body adapter heater plate with compressed air.
Inspection Procedure
1. Inspect the following:
- The sealing grommet on the MAP sensor for tears or damage
- The fuel rail mounting tabs for damage
- The intake manifold vacuum passages for debris or restrictions
- The composite intake manifold assembly for cracks or damage
- The areas between the intake runners
- The gasket sealing surfaces and grooves for cracking or damage
- The fuel injector bores for excessive scoring or damage
- The throttle body adapter heater plate for restrictions and/or corrosion
2. Inspect the following thread bolt inserts for looseness or damaged threads:
- Throttle body
- EVAP solenoid
- EGR pipe
3. Inspect the intake manifold cylinder head deck for warpage.
3.1. Locate a straight edge across the intake manifold cylinder head deck surface.
3.2. Insert a feeler gauge between the intake manifold and the straight edge.
A intake manifold with warpage in excess of 0.5 mm (0.020 inch), must be replaced.
4. Repair or replace the intake manifold as necessary.