P0420 and oil consumption on 200k

Discussion in 'Gen 2 Prius Main Forum' started by ghostwheel, Aug 20, 2021.

  1. ghostwheel

    ghostwheel Junior Member

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    I installed a cat shield to prevent my catalytic converter from getting stolen. Now I wish it would have....
    After a long road trip, my 2009 Prius, 200k miles, showed a check engine light, with code P0420. The service dept. said I need to fix the catalytic converter - they checked all the other options. The car had been burning oil for some time. I think it is getting worse. Probably 1qt every 1000 miles. I tried 44k cleaning, but it seems it didn't work all that well.
    Now the question is what to do.
    1. Clean catalytic convertor with spray or taking it off and using various chemicals.
    Reports seem to indicate this will not work
    2. Get a replacement cat, hopefully for less than my house costs. In theory, if stolen cats are being sold, I could sell mine as stolen, and buy a stolen one for zero cost difference :grin: I will not be able to bring myself to install a cat that doesn't work well
    Of course the problem is that if I install a new cat, it will fail soon (probably less than another 200k miles), because of the oil burn.
    So I could
    3. Ignore it, and hope the car dies before the new catalytic converter does.
    4. Try a piston soak as suggested here. I have to say that I'm quite afraid of that. (Though it could help me reach pt 3 above faster.) While doing the piston soak, I could do other cleaning - such as intake manifold and such...
    5. Try to get a new (old) cat and a new (old) engine.

    I'm still on the first hybrid battery.
     
  2. privilege

    privilege Active Member

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    I would use a 50/50 mixture of atf/acetone.

    1 disconnect 12v battery, leave keys in the house etc
    2 pull spark plugs
    3 fill each cylinder with the 50/50
    4 wait over night and vacuum it out there next day
    5 oil change, install plugs, run to full temperature
    repeat 3-4 times... it might help disable the carbon that is preventing the rings from sealing, if they haven't been run in this condition too long. if they have, a head gasket + ring job would fix it.
     
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  3. TMR-JWAP

    TMR-JWAP Senior Member

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    There's a lot of ideas/methods out there about how to reduce oil consumption. Hopefully one works for you, but don't over complicate the cat replacement. Replace the OEM cat with an aftermarket model (cost range of $140 to $500 depending if you want to replace the entire system or just the front portion). Sell the OEM for $1300-1500 or so, currently. Be done with it.

    These two are identical. I've installed a dozen+ on various Gen2s over the last year. No problems yet. I purchase a 1 3/4" heavy duty clamp from Oreillys to use with them instead of the clamp included with the cat. I can provide you with contact info for a recycler if you need it.

    Catalytic Converter 2004-2006 2007 2008 2009 for Toyota Prius 1.5L Front | eBay

    Catalytic Converter For 2004 2005 2006 2007 2008 2009 Toyota Prius 1.5L EPA OBD2 | eBay
     
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  4. privilege

    privilege Active Member

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    have you done many 3rd gen cats also?
     
  5. TMR-JWAP

    TMR-JWAP Senior Member

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    zero Gen 3. Ima Gen 2 kinda guy for the most part..
     
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  6. ghostwheel

    ghostwheel Junior Member

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    Thank you! Today is the first night. For now I filled with seafoam. Next night will be different. Maybe your 50/50. How to deal with the fact that half the pistons are closed and half open? I'm not totally sure of the best way to rotate the engine.
    I'm also not totally sure how to vacuum it back out. With a syphon? I'll check how deep I can get in there....
     
  7. ghostwheel

    ghostwheel Junior Member

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    Thanks!
    I'm trying to fix the oil consumption first. If that get's fixed, I'll replace the cat. If not... not sure.
    Do you know how well these cats work? Are they just cosmetic, or do they actually do their job, just less well?
     
  8. TMR-JWAP

    TMR-JWAP Senior Member

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    With 10s of thousands of miles on them, there haven't been any that have coded out, so at a minimum, they're better than a failing OEM. I've done some minor exhaust gas testing, but not at high loads, only idle type testing.
     
  9. TheLastMojojomo

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  10. ghostwheel

    ghostwheel Junior Member

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    Thank you! This helps a lot. I poured some Berryman's B12 in, and managed to turn the crank pulley bolt. I think. (see below. Though no 1/2" square drive hole)

    [​IMG]
     
  11. privilege

    privilege Active Member

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    the Pistons don't need to be the same part of the stroke. just pull the plugs and when you're done your can put a piece of fuel line down both your shop vac and into the spark plug holes.
     
  12. MilkyWay

    MilkyWay Active Member

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    We get them on eBay for about $100. Mechanic puts in for another $150. It will run better and code will go away.

    Also, the converter is worth anywhere from $400 to $1000 so you actually get paid to switch to aftermarket cat.

    Regarding oil burning...welcome to the club. I have had to check/add every 1500 miles since my 2008 Prius had 180k....It now has 280k.

    It only takes a minute so it's not a big deal to me. Never tried the piston soak but I'm curious about it.
     
  13. ghostwheel

    ghostwheel Junior Member

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    Things seem to be going well for now. (Well, except for managing to dump B12 over my forehead...) There is the question of exactly how much force is involved when you are supposed to "not force" a big lump of metal. For now it means I can't rotate the crank pully bolt clockwise any more. But it seems my B12 is seeping into the pistons.
    Of course the big question is how much damage have I done, and will my Prius ever restart.
    But if it all goes well, maybe I should write a "Piston soaking for dummies (or people who never changed a spark plug)" guide.
     
  14. ghostwheel

    ghostwheel Junior Member

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    Not so good. Maybe false alarm?
    After finishing the soak, mainly with Berryman's B12, I changed the oil, cleaned the MAF sensor and the throttle plate, changed spark plugs. The car did start, lots of white smoke. I drove around a bit, and then got a red triangle, together with
    P3190
    P0172
    P2196
    I rolled the car back down the hill, it made it home. Now I'm not sure what to do. Are these codes expected? Should I just bring it in to be checked? Should I have it towed to be checked?

    I disconnected the 12V battery, waited a few minutes, and reconnected it.
    When I turned the car back on, all seemed good. No more white smoke, no red triangle, no fault codes.
    Let's see how long this lasts...
     
    #14 ghostwheel, Aug 27, 2021
    Last edited: Aug 27, 2021
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  15. dolj

    dolj Senior Member

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    Probably running very rich induced by the remnants of the cleaner which produced all that white smoke. See how it goes, and keep us posted.
     
  16. TheLastMojojomo

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    Any updates?

    Posted via the PriusChat mobile app.
     
  17. ghostwheel

    ghostwheel Junior Member

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    OK, update. About 4 refuels later, the oil level is still up high. Normally we had to refill oil every one or two visits to the gas station. I think it was a success!
     
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