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2010 Gen 3 pushing coolant out of the overflow and loss of cabin heat

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Cheapjeep2, Jan 11, 2024.

  1. Cheapjeep2

    Cheapjeep2 New Member

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    I've got a 2010 Gen 3, it's been well used as it has 223k miles on it.

    I am having a few coolant issues.

    1. How can I test the fans, I would expect the fans to come on after the car has set in maintenance mode for an hour, they do not. They never kick on.

    2. I've noticed that the system is loosing a bit of coolant as it seems to be building pressure and pushing coolant out of the overflow bottle, I let it run in maintenance mode a while and shut it off, 2 hours later I could tell the overflow tank was swollen, I removed the cap as it cooled, but lost a TON of fluid as there was so much pressure. I did top it back off.

    Now yesterday I drove it and it started to over heat and I did lost cabin heat.

    I need to start to diagnose this again. Can't tell if I have a big air bubble trapped or where I need to start to diagnose.

    I am not sure if i have air trapped or a blocked cooling system. Appreciate your help.

    Troy
     
    #1 Cheapjeep2, Jan 11, 2024
  2. Brian1954

    Brian1954 Active Member

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    #2 Brian1954, Jan 11, 2024
    Last edited: Jan 11, 2024
  3. Kyra LeSene

    Kyra LeSene New Member

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    Make sure to check your thermostat as well. My girl was spitting up coolant out of the overflow tank and overheating, ended up being a blown head gasket. Make sure to check all your pumps, even the three way coolant control valve. One of your pumps isn't doing as it should!
     
    #3 Kyra LeSene, Jan 11, 2024
  4. bdc101

    bdc101 Member

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    If you have a 2010 you can also use the coolant bleeder valve to monitor if you are getting continuous bubbles generated from a blown head gasket (or just to bleed it after an overheating event like this). It is on the driver's side of the engine bay. If you connect a clear vacuum hose to it and zip-tie it to the hood, you can just watch it until bubbles stop coming out.

    However I'd agree with the others that you probably have either a blown HG or a failed water pump. Either one is likely at this many miles. And if you have overheated it then it's probably time to do both.
     
    #4 bdc101, Jan 12, 2024
  5. Mendel Leisk

    Mendel Leisk Senior Member

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    How long have you had it? If a recent buy, could be seller put stop-leak product in to mask head gasket failure
     
    #5 Mendel Leisk, Jan 12, 2024
  6. Brian1954

    Brian1954 Active Member

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    FYI, a Gen 3 does not have a three-way coolant value, but a Gen 2 does have one.
     
    #6 Brian1954, Jan 12, 2024
    Last edited: Jan 12, 2024
    CR94 likes this.
  7. Cheapjeep2

    Cheapjeep2 New Member

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    [​IMG] So some feedback..... It is not a new purchase. And yes I do know it has had head gasket sealer put in to tank.

    I just got it home today and checked under the hood and boom I see why it lost coolant so fast. I blew a hose off the little t-valve that comes right off the upper hose of the coolant bottle.

    [​IMG]
    [​IMG]
     
    #7 Cheapjeep2, Jan 12, 2024
    Last edited: Jan 12, 2024
    bisco likes this.
  8. Cheapjeep2

    Cheapjeep2 New Member

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    Ok, so tore into it today. Fans are working, thought they were not but they are indeed working. I tested every fuse relay and temp sensor and the fans directly.


    However, I have found the water pump is indeed bad, I can tell the impellers are fubar as I hear it grinding. This is a cheaper water pump I put in last summer.


    Anyone recommend a good reliable water pump?
     
    #8 Cheapjeep2, Jan 14, 2024
  9. Brian1954

    Brian1954 Active Member

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    When was the head gasket sealer added to the coolant?
     
    #9 Brian1954, Jan 14, 2024
  10. rjparker

    rjparker Tu Humilde Sirviente

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    The only reliable water pump is oem. Purchased from a dealer since there are counterfeits everywhere.

    The head gasket fail you confirmed with water in the cylinder is getting worse. The hose blew off due to pressure caused by running low on coolant. If the water pump is actually bad, it is likely due to steam and running without coolant.
     
    #10 rjparker, Jan 15, 2024
  11. Kyra LeSene

    Kyra LeSene New Member

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    Ahh, I apologize! As a gen 2 owner I sometimes forget the differences between the gen 2 & 3. Thank you for correcting me!
     
    #11 Kyra LeSene, Jan 15, 2024
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