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Overheating Light Came On.. x_x

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Partroob, Sep 15, 2019.

  1. Partroob

    Partroob New Member

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    So last night the overheat light popped up on my dash. There was no coolant in the overflow tank. Filled it up and went for a drive.. all the coolant came spewing out the overflow tank cap. I put a new o ring on the cap and ran the car until it started to pressurize. I took a video to show what is going on. I'm afraid to drive it the way it is as I believe something will explode due to the pressure. There is some strange noise coming from the water pump.. I'm assuming I am needing a new water pump.. but I wanted you guys opinion before I spend the 230$. What do you think? Here are 2 videos showing what's going on now. The towel is just so I could touch the pump without burning my hand.



     
  2. tankyuong

    tankyuong Senior Member

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    Looks like your head gasket is blown
     
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  3. Partroob

    Partroob New Member

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    I recently replaced my headgasket. No coolant is being burned or anything. It's just getting too pressurized and shooting out the top of the overflow tank.
     
  4. Raytheeagle

    Raytheeagle Senior Member

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    So the head gasket was replaced, but the water pump is the same?

    How many miles on your Prius?
     
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  5. Partroob

    Partroob New Member

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    Correct. Right over 220k. Bought it at 210k. Swapped headgasket at 211k.
     
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I agree that you should replace the engine coolant pump.

    Have you felt the radiator hoses to see if hot coolant is being pumped to the radiator? You would expect one hose to be hotter than the other.

    If you had a handheld infrared instant thermometer you could measure the temperatures of the two hoses and the engine coolant pump.
     
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  7. Pluggo

    Pluggo Senior Member

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    Running out of coolant left you with air pockets. Purge air from the system and bring the overflow tank to the proper level for a cold engine. Recheck it after you take a drive.
     
  8. Partroob

    Partroob New Member

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    Hmm. I think I only ran out of coolant due to this issue, though. I have driven 9k miles since the headgasket replacement so I don't think it would still be from that.
     
  9. Partroob

    Partroob New Member

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    Awesome, so if there is hot coolant going through both hoses, the pump is working fine?
     
  10. Patrick Wong

    Patrick Wong DIY Enthusiast

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  11. Partroob

    Partroob New Member

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    I put it in maintenance mode and ran it for about 20 minutes. Hoses never got hot and the water pump began screaming. It was screaming even when I turned the car off and started it normal with no has engine running.. ordered a new pump.
     
  12. Dxta

    Dxta Senior Member

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    You probably got air in the system.
    Bleed it properly and see what happens.
     
  13. E46Prius

    E46Prius Active Member

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    Cooling expert here (in general terms) You should check the coolant temp. The coolant in the tank is bubbling, likely due to boiling. And if it's boiling it can be caused by an underdriven water pump, or a totally dead pump, air in the system, or pressurization and/or exhaust gases via a headgasket leak.

    So without knowing the exact steps the mechanic used, the parts used, etc., it's hard to say what's going on here. Lets just hope it's something as simple as a water pump. It would be a coincidence that it failed right after the HG change.

    Also by changing the pump, you could inadvertently fix any bleeding issue when you replace the coolant, then incorrectly thinking it was the pump when it was really the act of changing the coolant. Anyway hope you get it fixed.
     
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  14. Rebound

    Rebound Senior Member

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    When I changed coolant in my Prius, bleeding the system was very easy, I just ran the heater and squeezed the fat hose with the reservoir uncapped. The Gen III had a coolant bleed screw in 2010 and maybe 2011. They got rid of it in 2012, probably because it was unnecessary.

    Bottom line: It’s easy to remove air pockets from the cooling system.... you should try it first, but the loud noise makes me think it’s the coolant pump.
     
  15. CR94

    CR94 Senior Member

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    My 2011 (made in March) does not have it. Will I have to take the top hose off the EGR heat exchanger to burp air out when I (partially) replace the coolant?