Still P0401 after cleaning egr !! should we drive it?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by ozmatt, Mar 27, 2021.

  1. AW82

    AW82 Member

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    So that's 104F...wonder what the temp of the EGR valve might have been at that point. And what the melting point of the plastic disc is... And whether Toyota engineers ever expected Aussies to do hillclimb races...
     
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  2. ozmatt

    ozmatt Active Member

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    Thanks Chapman.. okay got it, the valve is still on car I only removed the motor magnet and spring, will wind it on and check it seems to stop, and confirm it unwinds.. then straight to techstream for a step test .. Reluctant to put too much hand force on it as I'm sure that plastic is nowhere near as hard as it used to be, but it's good enough for today

    I'm expecting the stop position has moved inward by about 1mm or a smidgen more, which is a little more than I hoped it to move by but that's just how much it moved before I got the result I was chasing, shouldn't be an issue, I hope, maybe put the count out by one or two steps

    Looks a bit like petroleum jelly, probably is lithium grease though ..I have red bearing grease on hand lol bit messy but what's it matter I guess


    I'm still at the drink a ton of coffee procrastinate while looking out at the rain, stage of the morning ..

    .. bird is the word..

    Posted via the PriusChat mobile app.
     
    #122 ozmatt, Apr 8, 2021
    Last edited: Apr 8, 2021
  3. ozmatt

    ozmatt Active Member

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    We share all the same wonders :)

    Thing is this road sees a lot of cabs as it's the main highway for airport, and I don't hear about other locals having this issue..

    But those guys mostly drive camrys these days ..

    And mostly all their cars have check engine light always on lol, they know something is wrong when the check engine light goes out

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    #123 ozmatt, Apr 8, 2021
    Last edited: Apr 8, 2021
  4. ozmatt

    ozmatt Active Member

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    can definitely feel the stop position now, it seems quite good

    quick question, should i apply grease to the springs and everything or just the thread? only ask because it seems like the stout spring that lives in the rotor had grease on it but im not sure if its supposed to
     
  5. ChapmanF

    ChapmanF Senior Member

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    I think it's probably not necessary, unless you think you cleaned the springs off so thoroughly with such harsh solvents or something that there is now nothing protecting them from corrosion, in which case lightly smearing with your favorite grease or lightly spraying with WD40 or pretty much anything like that might bring peace of mind on that score.
     
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  6. ozmatt

    ozmatt Active Member

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    righto cheers mr ChapmanF

    stay tuned, about to try the (insert swear words here) thing!
     
  7. ozmatt

    ozmatt Active Member

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    Woohoo! Yeh boys only get to step 10 now and it's changing note, by 12/13 its starting to stutter.

    I'm calling it :)

    Thankyou so much for all the help everyone, I hope this helps others

    Now, who's got a spare magnet and spring :))?

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  8. ASRDogman

    ASRDogman Senior Member

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    Some high heat resistant grease on the threads is a good idea, maybe on the spring so it can
    slide smoothly. WD40 probably wouldn't last long after the first time the valve opens.

     
  9. ozmatt

    ozmatt Active Member

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    Hows it going Dogman.. i had some industrial rated red lith grease on the shelf so that's what it copped! half of what i applied got wiped back off, felt like it was compromising the rotors ability to self unwind and gave it an overall uneasy resistive kind of feel

    Grease applied to thread tends to find its way down and gather on the plate and too much grease packed between the rotor and base plate of valve where the stops meet together is not a good idea, also another point about that vulnerable area if you get too much buildup or debris in there it can stop the valve winding down fully to stop position and cause all sorts of dramas
     
  10. ChapmanF

    ChapmanF Senior Member

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    All the stuff being talked about for grease or spray is in the actuator portion of the valve, not where exhaust is flowing over it, and the springs don't need lube because they aren't sliding on anything ... just possibly a coating of anything for corrosion resistance and only if the OP was worried about having very harshly cleaned them in the first place. Even a cooked coating of WD40 would still probably suffice for that.

    And yes, it's good to avoid too much grease. The OEM didn't put a whole lot in there. Some of it did end up pushed off of the threads and piled up in places it did no good. I just scooped it back up from there and put it back on the threads.

    Whatever they had used for grease, it was white, and didn't seem cooked at all, after however long.

    Sounds like a successful repair. (y)
     
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  11. ASRDogman

    ASRDogman Senior Member

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    You just need to coat it, not pack it like a wheel bearing. :)
    Sounds like what you used will work. After a few thousand miles you can pull the top off and look at it.

     
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  12. ozmatt

    ozmatt Active Member

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    Hey guys, yeah I only put a touch on the thread, and half of what I put found it's way straight to the stop plate so I wiped it away! definitely not packed like a wheel bearing :)

    Successful test yes, repair, well.. maybe a touch early to call that but I will make note of odometer and leave it on the car, it buys me some time while hunting a spare magnet and spring to sit on the shelf for when it fails

    Thanks again

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    #132 ozmatt, Apr 9, 2021
    Last edited: Apr 9, 2021
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  13. ChapmanF

    ChapmanF Senior Member

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    Anybody notice the recent thread over in the c forum showing how that EGR valve even has the cooler juice routed through it, maybe keeping it cooler?

    juice.jpg
     
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  14. ozmatt

    ozmatt Active Member

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    no i didn't notice that, but i did notice when looking on ebay what looks like a cooler line on the gen4 egr valves
     
  15. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Just speculating: coolant would flow from valve to cooler? Or vice versa? Does it matter, lol?
     
  16. ozmatt

    ozmatt Active Member

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    Just found this while looking for egr valves on eBay, I imagine this would make the head gasket issue even worse than it already is?

    TOYOTA PRIUS MULTI FIT EGR VALVE BLANKING PLATE 1.5MM STEEL HA | eBay

    Also can anyone confirm if the rotor part of the egr valve is the same for the later part numbers ie 4th gen corolla hybrid etc, I understand the valve it's self is different but perhaps the rotor from 4th gens can be used in 3rd gen valve, anyone?

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  17. StarCaller

    StarCaller Senior Member

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    good question; obviously it works perfect for dozens of other car models /
     
  18. AW82

    AW82 Member

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    Interesting question. A related question: would head gasket failure occur if the four manifold ports clogged at the exact same rate (or if they never clogged but the EGR cooler itself clogged completely or the EGR valve failed and the car was driven 10s of thousands of miles)? Because if so, then the low-oxygen EGR gas may be necessary and blanking would likely make matters worse. If not, then maybe the ECU is smart enough to compensate for the presumed-even-across-all-cylinders lack of EGR gas (but can't tell there's uneven gas due to one clogged intake manifold port).

    Either way, I'm just going to clean the system and keep it as Toyota's engineers intended, even though they obviously made some mistakes.
     
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  19. Rocky Mountain Priusman

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    This is a good question. It seems that EGR cleaning is touted online as a preventative to head gasget failure. I am not really sure what the connection is, if there is any at all.

    It seems to me that EGR cleaning is the best way to keep your EGR from clogging and thats about it. Its a worthwhile endeavour in my mind, but I never understood it to be anything more than that.

    I should really say that I have 0 knowledge about even the basics of what causes a headgasget failure, other than somehow the gasget gets degraded and coolant and oil start to move through the gasget into the wrong systems causing big problems.
     
  20. AW82

    AW82 Member

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    Right. I'm basing the EGR-headgasket failure connection off of what people on PriusChat say, which is that headgasket failure tends to be associated with cylinder 1, and intake manifold EGR port clogging is typically worst for cylinder 1.

    People elsewhere say it's a thermal cycling thing...aluminum head and block acting differently than steel bolts and a gasket that couldn't make up the difference over the thousands/millions of on/off cycles that occur over 100-200k miles. Of course, that would imply that failures would be less common on primarily-highway-driven cars, which I don't think is the experience at least on PriusChat.

    Possibly it's a little of both...or neither...as many point out, there are hundreds of thousands of Prius owners that never post on PriusChat, etc.
     
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