2010 Prius, need some tips with maintanance and troubleshooting.

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by autosearx, Feb 12, 2022.

  1. autosearx

    autosearx Junior Member

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    2010 Prius
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    Hello everyone,
    I purchased my 2010 Prius last May with 140K miles and already drove it for about 7K miles.

    What was done so far:
    1. Oil was replaced twice, immediately after purchase and after 5K.
    2. Transmission fluid was replaced.
    3. Installed set of Nokian WRG4 tires.
    4. Changed cabin filter
    Problems encountered:
    1. Engine check light on, code P0420 (cat). No other codes.
    2. One rough start in the morning a few months ago. My coolant level isn't changing, and oil color is OK.
    3. After changing tires, my low tire pressure light turns on when I'm on the highway.
    Some data:
    1. First 5K miles, my MPG was around 45 (With AC always working, mixed city and highways)
    2. MPG dropped to 40 during winter, and after I replaced tires and oil.
    3. I got 35 MPG driving only in the city and traffic.
    4. Usually, I can reach 48-52 MPG on the highway with no problem.
    5. Best so far MPG was 56

    I was planning to go to Gasket Masters to get my head gasket replaced, just in case.
    But after reading some reviews and reading this forum, I decided to do DIY maintenance first.

    My current plan:
    1. Replace EGR cooler, valve and pipe.
    2. Replace air intake manifold
    3. Replace spark plugs
    4. Replace water pump (maybe)
    5. Install cat shield (maybe)
    6. Replace air filter
    I plan to buy new parts, just to save some time. I will clean old parts and keep as spare for next round of maintenance.
    I don't plan to replace catalytic right now, as I understood excessive oil burn might be causing code P0420.

    My questions:
    1. What else I can/need to replace? Fuel injector? Oxygen sensor?
    2. Do I need to update car firmware using Techstream after I'm done?
    3. What tools I must buy to make my life easier?
    4. What to keep in mind to not screw things up? I plan to do everything at once with my friend.
    5. Can you recommend a mechanic around NYC who has experience with 3rd gen Priuses? I had a very hard time explaining what I need.
    6. Would you recommend doing chemical analysis of engine oil? I saw some kits online.
    7. Would you recommend oil catch can? Can you provide some links to good ones?
    8. Would you recommend using thicker oil? Which one?
    9. Where to get PDF version of service manual?
    10. Any other tips?
     
    #1 autosearx, Feb 12, 2022
  2. bisco

    bisco cookie crumbler

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    welcome!

    is she burning any oil?
     
    #2 bisco, Feb 13, 2022
  3. autosearx

    autosearx Junior Member

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    Hi @bisco, I don't think she is burning oil. When I check my oil level, I don't see any change. How can I tell if my car is burning oil?
     
    #3 autosearx, Feb 13, 2022
  4. bisco

    bisco cookie crumbler

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    you would have less come out than you put in at oil change. if it was bad, you'd see it on the dipstick.

    it sounds like you have everything covered nicely, all the best!
     
    #4 bisco, Feb 15, 2022
  5. PriusGuy32

    PriusGuy32 Prius Driver Extraordinaire

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    Head Gasket replaced? Just in case?! Thats not something you replace "just in case". You only replace it when (and if) it fails. Its a very labor intensive job, and replacing the head gasket is not something you want to do if it doesn't need it.

    Clean your EGR cooler, tubes, valve, and Intake Manifold NOW. Yes, P0420 can be caused by an engine burning oil, and contaminating the delicate catalyst. Therefore, the catalyst will have failed from oil contamination, and need replacement anyways. However, on my last Gen2 Prius, the Check Engine Light was on with the P0420 code certainly caused by oil burning (the thing was a PIG with eating oil), so following suggestions on the Gen2 forums, I installed spark plug non-foulers on my rear downstream Oxygen sensor. It tricked the ECM into thinking the catalyst WAS functioning optimally, and the check engine light never returned.

    If your Prius IS consuming oil, you will want to address that lest you want to ruin another catalyst (if you replace it), and/or at the minimum, cake up your EGR circuit again. Search the forums for tips, many members have had success using High Mileage oils, a thicker viscosity (switching to 5w30, to 10w40, etc etc) depending on their oil consumption problem.

    You seem to be a proactive enough Prius owner, so I would suggest investing in Techstream software & an OBD2 cable. You will be able to see exactly why your TPMS light is illuminating on the highway. You might be surprised when reading the data; a sensor could be dropping out (low battery), the tire temperature could be significantly different than the others, etc etc. Generally tire pressure increases when you drive, not decreases. So the fact that the light illuminates on the highway is interesting. Have you actually checked the tire pressures?
     
    #5 PriusGuy32, Feb 15, 2022
  6. runnyeggs

    runnyeggs Junior Member

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    What’s techstream?
     
    #6 runnyeggs, Feb 18, 2022
  7. autosearx

    autosearx Junior Member

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    Thank you @PriusGuy32
    I replaced EGR cooler, PCV valve, intake manifold and cleaned EGR tube.
     
    #7 autosearx, Mar 12, 2022
    PriusGuy32 likes this.
  8. bisco

    bisco cookie crumbler

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    toyota diagnostic software
     
    #8 bisco, Mar 13, 2022
  9. slowmachine

    slowmachine Member

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    When you have new tires installed, it is common for the valve core to be removed for the fastest pressure bleed. It is also, unfortunately, common for the valve core to be reinstalled haphazardly and not fully seated in the valve stem, causing an air leak. If you have a $3 valve core tool, you can snug them up yourself.
     
    #9 slowmachine, Mar 13, 2022
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