Intake manifold bolts

Discussion in 'Vortec 4.2L I-6' started by BrownHP800, Dec 11, 2016.

  1. BrownHP800

    BrownHP800 Well-Known Member

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    Is there a video or tutorial on checking the intake bolts? I cant even seem to see them on my 02 Trailblazer.
     
  2. MRRSM

    MRRSM Gold Supporter

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    Pages 18 and 20 of the attached linked PDF White Paper show advantaged line imagery of where the Ten (10MM ??? or 13MM) Bolts are located along the Segmented Flange and usually are held fast with only 87 -89 Inch Pounds of force needed to clamp a good enough seal between the Plastic "O"Ring Oval Gaskets and the Aluminum Engine Head. It makes sense to tighten these from the middle area out towards the edges in an expanding circle and not over-tighten the Bolts.

    http://vortec4200.com/index_htm_files/vortec4200.pdf

    Be aware of the "Elbow Hose" that runs from the center bottom to the middle outer portion of the Intake Manifold as it conceals the presence of One Bolt Head underneath at the upper side of the "Zig-Zag" pattern along the Flange... and is both difficult to remove... and easy to destroy if you lose patience when trying to loosen it from where it attaches the Nylon Pipe.

    Having an assortment of 10-13MM Shallow and Deep "Wobble" Sockets with short, medium and long extensions might be helpful and using some Duct Tape to secure the Socket to the Extensions will make life easier when they don't drop off and wind up under the vehicle or somewhere inconvenient below the work area. The Fasteners are locked into the manifold and will not ordinarily come out unless force is applied... so if they all need to be removed and then new Gaskets installed... you won't have to worry about losing them when adjusting the IM back into place. These images can help you to visualize where they are "by feel"

    These first images show the New Style Intake Manifold for Later Model Vehicle...
    trailblazerintakemanifoldboltpattern.jpg trailblazerintakemanifoldboltpattern1.jpg trailblazerintakemanifoldboltpattern4.jpg trailblazerintakemanifoldboltpattern7.jpg

    This last image is of the Early Model Style.... Note the Small "Elbow Hose" in the Middle... The Brake Reservoir Hose is above and to the Right of it...

    trailblazerintakemanifoldboltpattern87.jpg
     

    Attached Files:

  3. webdawg

    webdawg Well-Known Member

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    Any recommendations on torquing the bolt @ the firewall? I could not get to it w/out a swivel.
     
  4. gmcman

    gmcman Well-Known Member

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    If I recall, I used a deep well 1/4" drive with a 1/4" ratchet. I believe 1/4" tools is all you can use anyway.
     
  5. Mooseman

    Mooseman Moderator

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    Honestly, I have never used a torque wrench on those bolts. Just guesstimated a good tight feel. Look at it this way, at the proper torque, they have backed out by themselves so a little over-torque can't hurt.
     
  6. webdawg

    webdawg Well-Known Member

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    See, when I did it, I wanted to torque. The big reason was, and it could have been because the gasket was old, that it was completely flat/useless when I took the intake off. I mean, it was not even touching the engine and it seemed recessed into the gasket trench basically.

    I did not want to over torque it.
     

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