Head gasket blown. Pink/orange tapioca. Have a few questions as to cleanup before proceeding.

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by weapon, Jun 22, 2026 at 3:13 PM.

  1. weapon

    weapon Junior Member

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    Oil level is fine and clean. Although it does burn oil and there is oil residue on the outside of the engine. I believe it is a blown head gasket but want to make sure.
     
  2. rjparker

    rjparker Tu Humilde Sirviente

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    A quality borescope inspection on a cold engine with a manually pressurized and full cooling system is the better hg test.
     
    #22 rjparker, Jun 25, 2026 at 11:01 AM
    Last edited: Jun 25, 2026 at 11:23 AM
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  3. weapon

    weapon Junior Member

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    This is the one, but if it is not correct for the prius then I will take it back. I have never used one before.
     

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  4. Mendel Leisk

    Mendel Leisk MMX GEN III

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    Something is not adding up? Maybe what’s in the cooling system is not motor oil? Have you ever changed engine coolant, any details?
     
  5. Mendel Leisk

    Mendel Leisk MMX GEN III

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  6. weapon

    weapon Junior Member

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    I am trying to flush the system not take it out for a road trip. Fill it with water, get it to operating temp then dump. Rinse and repeat until i get all of it out. Not going to do that 10 times with $40 a gallon toyota coolant. haha.

    I need to figure out a methodical process and that is why I am here for some help with planning assistance before I say screw it and just rebuild the head gasket or put a new engine in.

    Since I have cleaned the goop out of the easily accessed locations, next up is the harder places. What should be my next plan after the rinse and fill session?
     
  7. rjparker

    rjparker Tu Humilde Sirviente

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    If you don't see the fluid moving through the reservoir the thermostat has not opened.

    When the thermostat opens fluid flows through everything including the heater.
     
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  8. Mendel Leisk

    Mendel Leisk MMX GEN III

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  9. weapon

    weapon Junior Member

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    Yeah I am getting a lot of conflicting "help" so I am more confused than before. But that is ok. I have two of these so I am driving my alternate prius and big red is parked until i figure out a plan of attack.

    I have never changed the coolant in either but I had planned on doing all of the recommended maintenance on both cars which started last month. I have changed the oil regularly and done the trans fluid change in the spring. So I began on "my boy blue" with the egr cooler/manifold deep clean and that is when I noticed the new goop in big red after the check engine light came on. Parked it right away and came here to help diagnose.

    Wish I had a fellow prius enthusiast close to swing over and talk things through.
     
  10. Mendel Leisk

    Mendel Leisk MMX GEN III

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    So when you acquired the red one, someone else was the last to replace the engine coolant?
     
  11. weapon

    weapon Junior Member

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    This would be best cast scenario. The full system flush (multiple time) is my next step not matter what we talk about. That will start today as we dropped 15 degrees in daytime temp due to a cloud system moving in.

    Should I pull the water pump before hand and check to see if the goop is that low in the system? The bonus of the issue seem to be so far that the goop rose to the top and was in the high points. I used the syphon pump to get it out of the hose until is started sucking only pink coolant.
     
  12. weapon

    weapon Junior Member

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    I have no idea on maintenance by previous owner but it only had 70k miles and was in perfect operating condition as I paid for it to be checked by the dealership before purchase. As far as I know the coolant has never been changed.
     
  13. Mendel Leisk

    Mendel Leisk MMX GEN III

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    After initial 100k miles or 10 years (whichever comes first), it is supposed to be changed every 5 years or 50k miles.
     
  14. weapon

    weapon Junior Member

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    Good call. There has been no pink coolant come into reservoir since i added the water so it is still clear. I only drove it around my neighborhood for a few minutes then parked it and left it running so not sure if that was enough. Today my plan is to drive a bit longer and see if the flow happens.

    What do you suggest?
     
  15. weapon

    weapon Junior Member

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    That did not happen. (n) But it will be kept up to date from here on out.
     
    #35 weapon, Jun 25, 2026 at 11:53 AM
    Last edited: Jun 25, 2026 at 12:51 PM
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  16. weapon

    weapon Junior Member

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    Do you think I should put it in maintenance mode and cycle the water/coolant through the systems to see if the goop is throughout the system?
     
  17. rjparker

    rjparker Tu Humilde Sirviente

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    You need a scanner showing engine temperature as you drive with ac on. I can usually get normal temperature in 5 minutes. You can then see the flow entering the top reservoir hose using a flashlight.

    gen3 coolant reservoir flow.jpeg

    If you reach 200f or higher and no flow your engine is clogged up and or the water pump has failed. Normally the water pump would code.
     
    #37 rjparker, Jun 25, 2026 at 2:08 PM
    Last edited: Jun 25, 2026 at 2:32 PM