Is there a correct pattern for tightening the intake manifold bolts?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by weapon, Jun 27, 2026.

  1. weapon

    weapon Junior Member

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    My steps: All of them down to snug fit, then center, left outside, right outside, inner left nut, inner right nut and repeat until 21 ft lbf (As per the manual).

    Is there a factory recommended way or better order?

    I have a possible air leak somewhere and it is now throwing codes after clean install.
     
    #1 weapon, Jun 27, 2026
  2. ChapmanF

    ChapmanF Senior Member

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    It seems like you're looking at the same page in the manual that I am, and I don't see any specific order called out.
     
    #2 ChapmanF, Jun 27, 2026
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  3. Mendel Leisk

    Mendel Leisk MMX GEN III

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    In an @NutzAboutBolts video, and this seems plausible, they say something to the affect of "while there's no order noted by Toyota, it's prudent to start with the center, work out to the extremities back-and-forth.

    What code(s)? Will the engine run, or it just shuts down? Double-check both ends of the pcv hose are connected? That's easy to miss.
     
    #3 Mendel Leisk, Jun 27, 2026
  4. weapon

    weapon Junior Member

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    I mean I got it on like you would think it should go but was just wondering if there was an official order like the head bolts. Guess not.
     
    #4 weapon, Jun 27, 2026
  5. Mendel Leisk

    Mendel Leisk MMX GEN III

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    Nope:

    upload_2026-6-27_9-24-34.png
     

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    #5 Mendel Leisk, Jun 27, 2026
  6. weapon

    weapon Junior Member

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    Yeah. I have that manual pdf. Just states the ft pound not the order which seems strange.
     
    #6 weapon, Jun 27, 2026
  7. Tombukt2

    Tombukt2 Senior Member

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    Nope and you have a pretty good amount of silicone gaskets sticking up out of the groive area . Somlenty to. Make the seal.
     
    #7 Tombukt2, Jun 27, 2026
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  8. weapon

    weapon Junior Member

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    I ask because I just swapped in a cleaned egr and manifold and it started throwing error codes sputtering, puff of smoke and engine shut down (check hybrid system warning on screen). This is the second one I have done in the last few weeks and same as the first swap did something similar. So I had to remove everything and reseat all the parts then it worked fine.

    I am getting pretty quick at the removal and replacement though.
     
    #8 weapon, Jun 27, 2026
  9. Tombukt2

    Tombukt2 Senior Member

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    Yeah these plastic intakes are pretty nice they go on and off pretty easily minimal fuss . No buried fasteners and all of that stuff
     
    #9 Tombukt2, Jun 27, 2026
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  10. Mendel Leisk

    Mendel Leisk MMX GEN III

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    Throttle body hold-down nuts/bolts are similar: nothing in the Repair Manual, but it's good proactice to criss-cross when torquing. Torque for them is is 7 ft/lb (per attached). If you removed the associated studs, 44 inch/pounds (value per post 5 attachment) for them, a 1/4" drive torque wrench is appropriate for both
     

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    #10 Mendel Leisk, Jun 28, 2026 at 11:23 AM
    Last edited: Jun 28, 2026 at 11:29 AM
  11. ASRDogman

    ASRDogman Senior Member

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    What did you do after the first time you had this issue? Perhaps it the same issue????

    Usually, it's a not connected or loose connected connector. A vacuum hose not attack well enough,
    or at all. Check the pcv hoses, that is a very common issue.

     
    #11 ASRDogman, Jun 28, 2026 at 1:02 PM
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  12. weapon

    weapon Junior Member

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    I did not do anything really that different on the first car(my boy blue). Just took more care the second time. That car is running fine now.

    My plan for big red (almost 200k) in addition to reseating the manifold/looking for loose connections, is clean the plugs and the injectors as the ports were really full of carbon/oil buildup. Since the air box and wipers/shelf are all out it is pretty easy to do.

    Question: How much of the air box can I temporary leave off without causing any codes while I am testing?

    I figure I can seat the maf sensor plug into the lid and leave all the other parts out until i get this figured out. Kind of a pain having to remove all that stuff every time.
     

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    #12 weapon, Jun 28, 2026 at 2:06 PM
    Last edited: Jun 28, 2026 at 2:48 PM
  13. weapon

    weapon Junior Member

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    The answer to this hypothesis is: None. You do have to replace everything that you removed each time. It does not like air leaks and will throw codes, rough idle and not start if you try to not do the full install of the air box.

    In addition ASRDogman was right as I did also have the bottom hose come loose on the vacuum switching value assembly.

    Big red is now running fine and I will be doing the inverter fluid next.

    Thanks for all the help.
     
    #13 weapon, Jul 1, 2026 at 7:16 PM
    Last edited: Jul 2, 2026 at 1:03 AM
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  14. ASRDogman

    ASRDogman Senior Member

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    Glad it's running, and running well for you!
    It's usually something simple, unless you are yanking and jerking on parts.

    Vacuum hoses are the most common.

     
    #14 ASRDogman, Jul 1, 2026 at 7:57 PM
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