Lower Intake Manifold
The lower intake manifold (1) is an injection molded nylon composite design. The lower intake manifold is sealed to the cylinder heads using six individual press-in-place Fluoroelastomer (FKM) gaskets. Inspect the gaskets whenever the lower intake manifold is removed from the engine. The gaskets may be reused if no issues are found. The eight upper intake manifold fasteners thread directly into the composite lower intake manifold and are a self-tapping design.
The four fuel rail fasteners also thread directly into the composite lower intake manifold and are a self-tapping design. The lower intake manifold can be serviced without removing the fuel injector rail. The fuel rail and fuel injectors must be installed into the lower intake manifold as an assembly. Do not attempt to install the fuel rail when the injectors are in the manifold. Always install new O-rings on the fuel injectors.
If the lower intake manifold is damaged or cracked, it must be replaced.