Bottom EGR Cooler Nut Accessible From Bottom?

Discussion in 'Gen 3 Prius Main Forum' started by pingd, Oct 4, 2019.

  1. pingd

    pingd Member

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    Having a devil of a time breaking the bottom EGR cooler nut (i.e. bottom of the pair of bolts that connect the EGR cooler to the exhaust manifold).
    Yes I Kroil'ed it for several days now - top one broke OK.

    What I'm trying to do starts at appx 7:05 in the NAB video "2010-2015 Toyota Prius EGR and EGR Cooler Cleanings for P0401 Code".

    Would this nut, and the subsequent stud removal, go better from the bottom? (i.e. jack the car up)
    Bottom plastic shield and intake manifold are both completely off at this point.
    Yes I also got one of those nifty palm ratchets&flex head 12mm ratcheting wrenches&12mm deep sockets that NAB used ... so I think it will go OK once I break the nut/stud.

    Thank you!
     
    #1 pingd, Oct 4, 2019
    Last edited: Oct 4, 2019
  2. Raytheeagle

    Raytheeagle Senior Member

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    You can do it from below;).

    I did it that way the first time I did our old 2010’s cooler:).

    Good luck with the cleaning and assembly process and keep us posted (y).
     
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  3. Mendel Leisk

    Mendel Leisk Obtuse Angler

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    For removal, I reached that nut from above, played around with various ratchet wrenches, sockets (normal and deep) and various extension lengths. You need just the right length of extensions to be able to fish through the mishmash of cables and hoses to the right of the EGR (as you stand at the front of engine). 3" and 6" extensions are good to have on hand, and 1.5", for fine tuning. I believe I needed the 1.5", and maybe a 3" as well. Stubby and deep socket help to finetune the reach further.

    I was using a sweet long-handled Jet wrench with a swivel head, which helped too. The swivel head makes it easier to snake it in straight, then unswivel, bring the handle back closer to 90 deg, once you've got the socket on the nut.

    Going in with extensions, I believe that nut is just beyond and a little low, offset from a largish coolant hose going into the head. Say around 4:30, if the coolant hose was a clock face.

    FWIW, you can touch the nut, if you reach all the way around the EGR cooler from the left side, clockwise reaching around. Doesn't help much when you're trying to break it loose, but does when reinstalling, or to catch it during removal.

    I believe @Raytheeagle doesn't reinstall that nut after. The more I think about that, the brighter it sounds. :)
     
    #3 Mendel Leisk, Oct 5, 2019
    Last edited: Oct 5, 2019
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  4. Raytheeagle

    Raytheeagle Senior Member

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    One option I’ve been doing on that lower back but is simply use the E8 torx socket and rotate that out;).

    Why mess with the nut if you don’t have too since you’re removing the stud anyway:whistle:.

    And I do not reinstall the lower cooler support nut which fastens the cooler to the engine block (that’s off topic for the OP’s question, but since @Mendel Leisk brought it up thought I’d share). There is a stud there for alignment and there are at least 5 other ways to support and stabilize the cooler into place:).

    One less nuisance the next time(y).
     
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  5. pingd

    pingd Member

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    Many Thanks to you both Master Jedi Ray and Master Jedi Mendel - armed with such hard fought and clever insight ... I must surely prevail!
     
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  6. Mendel Leisk

    Mendel Leisk Obtuse Angler

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    The night before I got into the EGR removal, I started by working on that one nut, wanted to make sure I could reach it and get a purchase on it, break it loose.

    Further, regarding the need for that nut: @Ragingfit installed a 3rd gen EGR system on a 4th gen engine, a couple of times now (in a 3rd gen Prius and Prius v): none of the intermediate bolt locations work, so it free-spans from the exhaust to intake manifold connections.
     
    #6 Mendel Leisk, Oct 5, 2019
    Last edited: Oct 5, 2019
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  7. pingd

    pingd Member

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    UPDATE:
    Removed the bottom EGE cooler nut!
    But my joy was short lived because, after breaking the bottom E8 Torx stud from rust ... the head of it snapped clean off while trying to unscrew it (about 80% of stud remains).
    Got everything else off the EGR cooler ... I can wiggle it a bit ... but either it is "welded by heat" at the exhaust manifold side, OR, the bottom stud (80% length) is somehow preventing it from sliding out towards the front of the car.

    So now I'll have to go gorilla on it, or, hacksaw/Dremel/locking pliers the busted stud out of there ... I guess from the bottom.
    And then to compound the problem, although I ordered spare E8 Torx studs to replace the original (rusted) ones, they were not in the shipped box ... and I had to pay full price from the local stealership (luckily in stock though).
    AAArrrggghhhh %$^@^&*!!

    Luckily too I have a brand spanking new EGR cooler to put in once out (ebay/$175) ... so at least I won't have to clean it this round (153k miles so it'll be pretty clogged methinks).
     
  8. pingd

    pingd Member

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    Jacked the front end up ... unable to understand how one might reach it from that vantage point though.
    Double-checked that all bolts and hoses are off otherwise ... even the (lone) stud+nut that's at the "top" of the EGR cooler assembly ... check!

    Can't think of anything else to do other than to keep wiggling it ... cautious about jamming a wedge (flat head?) in-between the EGR cooler<->exhaust pipe mating point. (I have a new gasket but I don't want to damage either mating surface).
    Going to Kroil up the gasket at the mate point, and what remains of the stud, to see if that loosens anything up.

    Could it be that, over the 153k miles some exhaust gases have escaped and caused the 2 surfaces to "weld" (basically corrode together)?
    Has any other person reported extreme difficulties with this step?
    THANK YOU!
     
  9. Mendel Leisk

    Mendel Leisk Obtuse Angler

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    Mine was nowhere near that bad. Chalk it to 150K miles and nasty winter localle?

    Just to verify: you're aware the bottom stud, the one with the nut removal we were discussing before, does not need to come off, to get the cooler off?

    Standing a the driver's side fender, you just pull the cooler towards you. That's how @NutzAboutBolts manages, in his video.

    About 11 minutes in he's getting close:



    At 12:40 he mentions no need to remove the bottom stud.
     
    #9 Mendel Leisk, Oct 5, 2019
    Last edited: Oct 5, 2019
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  10. pingd

    pingd Member

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    Agreed about Rust Belt woes!
    Yes, understood about the bottom stud.
    I'm exactly at that point where I should be able to just pull it forward and declare victory.

    The top nut+stud are completely out.
    I'm 100% certain the bottom nut is off too, and, that I broke the rust bond on the stud.
    Then I'm also certain the last 20% of the stud broke off (i.e. the star pattern end of the stud).
    I'm also 100% certain I have removed the 12mm nut AND stud in the front (90 deg to the others)(at 11:20 in the video).

    I have a spare EGR cooler and I hold it up to the actual workspace, noting all the hose and bolt connections (to be certain it should indeed be free to slide forward).
    I can push down on the front of the assembly and see the metal gasket separate and slide around ... moves 2-3mm up/down maybe.
    I can't really twist it (left-right, maybe 1mm), just wiggle it up and down.
    The only place I feel it binding is that bottom stud.

    From what you say no one else has noted such extreme binding at that area ... so it must be rusted together (or bent, I suppose).
    I guess, just keep at it with: Kroil and wiggling and trying to pull forward as you've noted Sir Mendel.

    Thanks again!
     
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  11. Raytheeagle

    Raytheeagle Senior Member

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    The job isn’t tough but you are starting to see how fiddly it can be;).

    I’ve tested my skills to the point where I did the egr cooler swap WITHOUT removing the windshield wiper cowling :whistle:.

    Wouldn’t recommend that method though as it is time consuming :cool:.

    Where there is a will, there’s a way. Keep your head up and you’ll get there:).

    I wouldn’t suspect welding of components, just be difficult (y).
     
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  12. Raytheeagle

    Raytheeagle Senior Member

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    I’d say remove the lower stud from under the cooler to engine block connection and you’ll have only one point of resistance ;).

    That is also an E8 torx socket stud, so you have the tools you need:).

    Another option to get you through(y).
     
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  13. Mendel Leisk

    Mendel Leisk Obtuse Angler

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    Maybe just a stupid question: you've got these two nuts and studs removed?

    upload_2019-10-5_18-18-48.png
     
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  14. cnc97

    cnc97 Senior Member

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    The more of these EGR threads I read, the more I’m glad I got a “Florida” Prius.
     
  15. Raytheeagle

    Raytheeagle Senior Member

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    Think of the studs present there as a triangle;).

    If you remove 2 of the 3 sides, you’ll have what you need to proceed and remove binding(y).
     
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  16. Mendel Leisk

    Mendel Leisk Obtuse Angler

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    Yeah back studs, connecting to exhaust comes out. And IIRC the front stud, at the underside of the valve, also comes out (could check the video to confirm)*. But sure as shooting the bottom stud can be left as-is.

    * yeah, that stud comes out, around 11:50 of @NutzAboutBolts video above.
     
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  17. Raytheeagle

    Raytheeagle Senior Member

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    A cool head often prevails when faced with an issue;).

    Breaking a stud can be stressful, but isn’t the end of the world:).

    I’d leave the snapped piece as is for now a figure out a way to get the job done and deal with the stud when not in a compromising position :eek:.

    Better to work in an ergo friendly way when problem solving (y).
     
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  18. pingd

    pingd Member

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    THE MAGIC WAS TO REMOVE THE STUD TO THE NUT THAT NAB REMOVES AT 10:30 (i.e. in addition to the NUT that NAB and me removed, I ALSO had to remove the STUD).
    Thanks kindly Ray ... the triangle image made me instantly understand what I was missing ... what a bonehead!

    Mendel, also thank you for the pics and advice.
    [In answer to your question: "Maybe just a stupid question: you've got these two nuts and studs removed?" I HAD BOTH NUTS OFF, BUT ONLY THE TOP STUD REMOVED ... BOTTOM STUD BROKE OFF NEAR THE TORX HEAD.]

    So, now I'm on to doing the valve cover gasket, spark plugs, PCV, clean EGR pipe, then reassemble with clean/new: intake manifold, EGR tube, EGR cooler, EGR pipe and some fluid changes.
     
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  19. Mendel Leisk

    Mendel Leisk Obtuse Angler

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    Ok, understand now, I think. The broken stud is the lower one, at connection to exhaust manifold. Also, by removing the stud on the "hidden" connection, the troublesome one on that extended bracket on underside of cooler, then you're able to fish the cooler out, broken stud and all?

    You can track down the stud part no on this page:


    EXHAUST GAS RECIRCULATION SYSTEM. 2013 Toyota Prius Two HYBRID | Toyota


    upload_2019-10-6_8-21-0.png

    This specifically, which looks to be a revised part:


    2013 Toyota Prius Two HYBRID Bolt. Interchangeable with 90126a0019 - 9012608052 - Genuine Toyota Part
     
    #19 Mendel Leisk, Oct 6, 2019
    Last edited: Oct 6, 2019
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  20. pingd

    pingd Member

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    Thank you again Sir Mendel.

    Yes, as far as I can determine, the original stud (90126-08052) has been superseded by 90126-A0019.
    AND I can confirm, Mr Mentat :cool: comparing the original to 90126-A0019 they look the same to me.
    (hopefully you're catching the reference to the book, Dune by Frank Herbert ;))
     
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