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Spark plugs replacement - maybe a stupid question...

Discussion in 'Gen 3 Prius Technical Discussion' started by Lares_Mat, Feb 23, 2024.

  1. Lares_Mat

    Lares_Mat Member

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    Hi!

    My Prius 2010 is a little above 100 000 km (between 62 000 and 63 000 miles) and I'm planning to replace the spark plugs myself.

    The stupid question is, do you really need to remove all the cowl stuff and the wipers?

    I've bought access to Toyota repair manuals for an hour (Europe), found there the procedure, but they do not write _anything_ about removing anything besides the cylinder head cover no 2 (the plastic one), the coils and the plugs themselves...

    Of course, I read a lot about spark plugs and the replacing process, watched a lot of YouTube, and everywhere I find, they are removing a lot of stuff.

    So, why Toyota does not recommend removing the cowls?

    Where, by removing the EGR cooler, they explicitly instruct you to remove the cowls and give you all necessary steps, to do it...

    Maybe, the question is stupid, but, if you do not ask, you do not know ;)

    Mat
     
  2. JC91006

    JC91006 Senior Member

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    Mat, if there is a way to remove the coil packs and plugs without removing the cowl, you can do that. But from my experience, this can't be done without removing the cowl.
     
  3. Lares_Mat

    Lares_Mat Member

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    Yes... If it could be done, all YouTube mechanics would do it this way...
    But...
    Why wouldn't Toyota (so thorough in the repair manuals) write it down...
     
  4. amarino

    amarino Member

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    Is it for UK / RHD cars? Can you share a screenshot or PDF or what the European manual looks like?
    It looks like it is possible for RHD Gen 3 Prius to change spark plugs without removing the entire cowl:

     
  5. Danno5060

    Danno5060 Member

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    Try it. If you can pull the coils and spark plugs out of the holes it works. If not, you're really not going to be wasting that much time.

    As usual, with spark plugs, hand tighten them for a few threads to make sure they're not cross-threaded.
     
  6. Mendel Leisk

    Mendel Leisk Senior Member

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    Right-hand drive I think there's just enough room. But other'n that, if you disconnect the coils and try to pull them out, they bump into the cowl or related, an inch or so too soon to be able to fish them out. It's a sand pounder for sure.
     
  7. Lares_Mat

    Lares_Mat Member

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    My goodness...

    I just came back from my garage. I took the cover of and looked at the spark plugs and was about to write this:
    Okay, guys... I guess I have to apologize to you for asking this... well... stupid question... I just came back from the garage where I removed that plastic head cover... It is not possible to remove the ignition coils and then the spark plugs without removing the covers under the windshield...

    But now?
    I asked this question actually, while I thought, I heard some time ago, one could replace the spark plugs without dismantling all the cowl stuff...

    The sad news is, under the video in the comments one can read:
    @johnschaefer4129
    wondering why this for RHD only? the lower cowl clearance is different, so that you can use a jointed extender for the tool?

    @unkertech
    Yes. The LHD version have a bigger lower cowl that must be removed. Whereas the RHD have smaller cowl to allow the coil packs removal.


    So - maybe the question was not THAT stupid, but maybe it really is impossible to quickly replace the plugs on a LHD Prius...

    Mat
     
  8. Tombukt2

    Tombukt2 Senior Member

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    By the time you do all the fighting you could have had the 10 bolts that hold the cowl in and the five bolts that hold the wiper in or whatever it is they blast out as fast as I'm talking so you'd be finished with that and America another way you could do it is put a hole in the wiper tray or put four holes in the wiper tray right above the coils it'd be about an inch and a quarter with your hole saw so you can just undo the coil 10 mm pull them through the holes you made in the wiper tray etc etc but since you're only doing this every hundred thousand miles which for some of you people is a very many years I don't even know why you would bother It's the same in my sienna van and you can whip that tray out quite quickly it just looks like a lot of mess it's really not even in the generation 2 where you don't have to remove the tray to do the plugs You have to remove it to get it to break actuator I can pull that tray out and about 7 minutes so as time goes it's just not worth making up a workaround it doesn't seem like.
     
  9. Lares_Mat

    Lares_Mat Member

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    What fighting?

    I do my research. I'm not a mechanic, but I want to replace my spark plugs myself. And I want to do it right.

    It would be nice to do it without undoing that many bolts and nuts.
    If it is inevitable, I will of course do that!

    At least we know now, that RHD and RHT are not the same in this aspect.

    Mat
     
  10. ChapmanF

    ChapmanF Senior Member

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    Yeah, for those of us with the double-jointed passenger wiper, "remove the wipers and cowl" is just the first step of so many procedures in the repair manual, it's like the "chop ½ onion" at the start of just about any recipe. You start not even noticing you're doing it.

    One difference: removing the wipers and cowl doesn't make me cry. Advantage Prius.
     
  11. jerrymildred

    jerrymildred Senior Member

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    It takes me 10 minutes (I've timed it) to get the wiper and cowl assembly out of there with an impact driver. But I've done it dozens of times. It'll take a first timer longer, especially if you don't have an impact driver or a battery powered ratchet. Be careful that you don't crack the windshield when removing the fasteners for the bottom of the cowl. Your extension if using an impact driver is close to the unprotected bottom of the glass.
     
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  12. ChapmanF

    ChapmanF Senior Member

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    The repair manual also warns you to be careful not to crack the windshield when lifting the plastic cowl grille out. Clips in its top edge fit onto the bottom edge of the glass. Be sure to slide it down away from the glass before lifting it.
     
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  13. Lares_Mat

    Lares_Mat Member

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    guys!

    Thank you for your tips and answers!

    10 minutes - yeah ;) With a ton of experience and with power tools - it is possible for sure.

    I will be doing it for the first time, so the procedure and tips like yours are crucial.
    I'm not afraid of work like this, but why should you do something, that is not necessary - this was the source of my (maybe not so) silly question.

    What is wondering me - I really saw the repair manual pages, and there is absolutely nothing said about taking out the wipers and cowls. No mention about LHD and RHD...

    I looked at the dismantling of the EGR cooler too, and there you have all the steps to remove the wipers, cowls (draining the whole coolant ;)) with all warnings about the windshield and so on.

    Mat
     
  14. Mendel Leisk

    Mendel Leisk Senior Member

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    if you’re only doing EGR, I’d just drain 2 liters, from radiator into clean container. This will leave EGR components above the coolant level, more or less dry. Throttle body coolant lines don’t need to be disconnected if it’s lifted off for intake manifold removal/cleaning; they have sufficient slack.

    see my signature for more details, top two links (on phone turn it landscape to see signature).
     
  15. Lares_Mat

    Lares_Mat Member

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    Thank you Medel! I know that - I read your posts carefully - this is why I have put the emoticon next to this sentence.
    I plan to do it like that.
    I know too - to clean the throttle body, I do not have to disconnect the hoses, neither.

    I always wanted to ask you - are you sure about the 2 liters? Not more?
    Of course, I have to be careful not to pour the few remaining cubic centimeters of coolant from the EGR cooler into the engine bay, but they are maybe not that critical ;)

    Do I have to do something specific to get the air bubbles from the cooling system out? Or is it too little coolant drained to suck any air in?
     
  16. Tombukt2

    Tombukt2 Senior Member

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    Mike has been said you don't drain the coolant You just let a little out unless you've got a lot of oil in your coolant or something The windshield cowl taking out is pretty self-explanatory You take off the 14 mm wiper hold down bolts there's three of them one's under a plastic cover I do believe on the wiper arms and they lift straight off drop them in the trunk or on the ground lift up the plastics expose the tray put the plastics on the ground or in the trunk Don't lose the little corner pieces sometimes they fly off You lose them you'll never replace them and you got an air noise on the right side. Take out the 10 mm wiper transmission hold down bolts zip zip zip notice their special length they don't look like the rest of the bolt so you don't need the bag and tag them separately put them next to the wiper transmission on the ground or in the trunk. Now you feel the floor of the metal tray that is your wiper tray and you'll find 2 4 6 or 8 bolts you blast those out with your little gun leave them in the tray pick up the tray disconnect the wiring harness clips that are being held by the tray for the wipers and what not set the tray off to the side that should have been no more than about 12 minutes and now you have complete access to your spark plugs coils brake actuators other things on the firewall many times when I'm working on the brake actuators on generation 2's I'll leave the wiper tray out for a week That's why the windshield is very well coated with Rain-X. Matter of fact the generation 2 I'm driving now hasn't had the wiper tray in it for about 68 days no problem driving in the rain with Rain-X that's the way we've always done it and good luck with your project try to get real spark plugs The fakes will fall apart leave pieces in your engine not a good thing Best to round up a real supplier that you can trust and that is important back in the old days I was able to call nipppodenso direct in cali. And get sample pieces and what not sent directly to my shop without any problem now I'm sure that's probably not possible as everything has been ruined in that genre this was like in the '87 through 90 when denso opened up shop somewhere in California not far from TRD when TRD was a small hole in the wall and didn't have any stickers yet and there were no trucks to work on this is for real racing development for the 4T GTE in the gruppe B rallying days.
     
  17. Mendel Leisk

    Mendel Leisk Senior Member

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    I worked with a Romanian engineer, asked him one time how he decided what to do, some renovation we were looking at. He licked a finger, held it up, to illustrate testing wind direction. That’s about how I came up with the 2 liters.

    Just pouring it back into reservoir, nothing much extra, worked out ok for me. It was a little higher, but settled back down. I did open the coolant vent spigot while filling (have 2010, other years may not have this), poured slowly, and gave coolant hoses a few squeezes.
     
  18. ChapmanF

    ChapmanF Senior Member

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    I saw a video once of igniters being removed from some other make of car, and I backed up and frame-stepped through the video, and sure enough, that car used igniters where the long stem part was flexible! The mechanic just lifted and bent them out from under the cowl on that car.

    If our igniters were like that, you probably would be able to sneak them out and back in without cowl removal, even on the cars with the double-jointed windshield wiper.

    Maybe somebody sells a floppy-igniter compatible replacement for Prius. Then you could replace the original igniters with those (to save taking the cowl out, you could take a hacksaw to the original igniters). Then you'd never need to take the cowl out after that. (Except for all the other procedures that need the cowl out.)

    Another approach could be to go under the car and disconnect the amidships engine mount, the one that links the bell housing aft to the transverse member to restrain engine roll. Then with a jack under the rear of the engine, you might be able to roll the engine forward just enough to get the igniters out despite the cowl.
     
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  19. Lares_Mat

    Lares_Mat Member

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    Hello Tombukt2!

    I managed to get through your response... Not easy to read and understand if you are not American. ;)

    I know the official procedure - the partial drain of coolant is not official, so I wanted to be sure, I understand it right.

    You mentioned Rain-X. I don't know if I can buy it in Europe, but it sounds tempting to try ;)

    I have a LHD Prius, so I have to stick to the standard procedure - no problem.

    Mat
     
  20. Lares_Mat

    Lares_Mat Member

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    OK, so I will stick to the 2 liters and see what happens. ;)
    Didn't you mention lifting the front of the vehicle? If yes, is it important?
    I can use a car repair pit in the garage of my parent's house, so I plan to do it there.

    Mine is 2010 too, and it has the spigot - will connect a PVC hose, open it and pour back the coolant into the reservoir.

    I like the "finger in the wind" parallel. You have to have a lot of experience to work like this, tho.

    Mat
     
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