Another EGR thread

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by darknd666, Apr 1, 2026 at 12:01 AM.

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  1. darknd666

    darknd666 Junior Member

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    Would letting a 1/4 cup of marvel mystery oil in each cylinder help or harm? To help break up the crud? Regardless if the head comes off im just going to have better access for a deeper cleaning.
     
    #41 darknd666, Apr 1, 2026 at 9:16 PM
  2. darknd666

    darknd666 Junior Member

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    Where would I get the software update file?
     
    #42 darknd666, Apr 1, 2026 at 9:37 PM
  3. rjparker

    rjparker Tu Humilde Sirviente

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    Caked up is better than clean enough to see aluminum color on parts of a piston. In your case the cheap borescope is non-conclusive for a head gasket leak.

    You can not just look unless you see a pool of liquid or one cylinder is shiny and the rest are carboned up. You pressurize the cooling system to 15 psi with a cold engine and use a dual view or articulating scope to observe the cylinder walls and head gasket. Then you wait for one or two drops. Hopefully they don't come.

    Do not pour liquids into the cylinder regardless if its Marvel or not. That is hydrolock and junk engine time ready to happen.
     
    #43 rjparker, Apr 1, 2026 at 9:40 PM
    Last edited: Apr 1, 2026 at 10:04 PM
  4. rjparker

    rjparker Tu Humilde Sirviente

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    For an ecm update you need to buy access to the Toyota TIS system and have the latest Toyota Scanner software running on a PC with a hardwired Mongoose usb to obd2 interface. Its cheaper and safer to let Toyota do it. I would not worry about it until you have a trouble free engine. Then consider updating the ecm software.

    Latest Global Techstream+ required along with a $545 Mongoose interface. You supply an adequate Win11 pc.
    Image.jpeg


    Global Techstream+ download and two days authorization is $80. Includes calibration files for updating your ecm or other ecus.

    IMG_1009.jpeg

    Better to let the dealer do it unless you are a shop with continuing requirements of this kind.
     
    #44 rjparker, Apr 1, 2026 at 10:04 PM
    Last edited: Apr 1, 2026 at 10:24 PM
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  5. darknd666

    darknd666 Junior Member

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    I wasnt expecting to see anything that would confirm what we are suspecting. Simply did it on the whim that it might if there was a leak and it was really bad. I agree though for a leak that small i would have to pressurize the system for a while and check for coolant in the cylinders.
     
    #45 darknd666, Apr 1, 2026 at 10:05 PM
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