Intake Plastic Plenum Torque Specs and Tightening Sequence

[Fitz98]

98 Expedition 5.4 4x4
Does anyone have the tightening sequence and torques specs for the ALUMINUM intake manifold to the heads and the PLASTIC plenum to aluminum intake?
I saw plenty of resources online with the information, but not much that defines the specs specific for the plastic and aluminum components

 

[bdcardinal]

Hope it helps.

 

[Fitz98]

Yep, that's the one I have been seeing. Is that for the aluminum intake to head and plastic plenum to intake?

 

[bdcardinal]

The first one is the plastic plenum to the bottom of the intake and the second one is the intake to cylinder heads.

 

[Dave9]

You may want to re-torque the plastic plenum after a few hundred miles, if it's the silicone rubber gasket type it can settle and become loose.

 

[Fitz98]

Originally Posted by Dave9
You may want to re-torque the plastic plenum after a few hundred miles, if it's the silicone rubber gasket type it can settle and become loose.

Interesting you would bring that up.
I had new gaskets installed when the motor was installed, but since I have the intake removed (I won't be removing it again, unless there is a problem), I figured I would just replace the intake gaskets while I have easy access. So my options are to replace the plenum gasket with a new one, or just re-torque the one that was installed a couple years ago and hope the gasket that was installed holds up.
What is the function of that plenum anyways?

 

[user52165]

Never reuse a gasket here. New always. Plenum is an extension of the intake manifold - 2 pieces rather than one for weight and cost saving.

 

[bdcardinal]

Originally Posted by user52165
Never reuse a gasket here. New always. Plenum is an extension of the intake manifold - 2 pieces rather than one for weight and cost saving.


That and trying to cast it in one piece might have been beyond the capabilities at the time.