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Prius Gen 3 overheating Uphills

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Mt Bajwa, May 8, 2022.

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  1. Mt Bajwa

    Mt Bajwa New Member

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    I bought a Prius 2011, my first hybrid car. A few days ago I had a coolant leak and the engine coolant pump died, got a p261c(IIRC). I replaced the pump. The car drove fine. Today I was driving uphill, the weather was around 40C and the car was on full load (5 persons). I got a high temp light (red sign, no CEL or triangle). Checked the coolant temp with torque and it was around 106C. Waited for the car to cool and decided to return home (downhill and then city drive). Didnt get a warning again. But I am worried as to why that happened.
    I have checked
    -coolant level (FULL)
    -fans (start working at 94C on torque app)
    -the car seems to be returning coolant to reservoir
    -Also tried to bleed coolant air pockets( heater on and engine revving in maintenance mode)

    Need expert opinions on what might be the problem.
    Thanks.
     
    #1 Mt Bajwa, May 8, 2022
  2. 2010moneypit?

    2010moneypit? Active Member

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    After replacement of the pump did you get all the air out of the system? If so how did you get the air out of the system?
     
    #2 2010moneypit?, May 10, 2022
  3. StarCaller

    StarCaller Senior Member

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    #3 StarCaller, May 11, 2022
  4. ChapmanF

    ChapmanF Senior Member

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    How long between the warning light and when you checked that temperature?

    The warning light doesn't come on for engine temperature until 120 ℃*. So if you had the light on and you saw the engine coolant at 106 ℃ right away, then it wasn't the engine over temperature, but one of the other coolant temperatures in the car. Did you check all the inverter and MG temps?

    On the other hand, if you saw the warning light and then the engine had a chance to cool some before you read the 106 ℃, then maybe it was the engine after all and it did hit 120 ℃ at that earlier point where the light came on.

    * The Gen 3 engine has two coolant temp sensors. I've tested this for the one that's in the EHRS return hose. I haven't done the same test for the one in the cylinder head, so possibly that one could have a different trigger point for the warning light. But I know it's higher than 107 ℃.
     
    #4 ChapmanF, May 11, 2022
    Last edited: May 11, 2022
    ThePrius11 likes this.
  5. redprius2011

    redprius2011 Junior Member

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    #5 redprius2011, May 19, 2022
    Last edited: May 19, 2022
  6. redprius2011

    redprius2011 Junior Member

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    My gen 3 engine automatically shuts down when its getting hot because my water pump failed, but i don't think that gen 3 engine head gasket can survive at 120 degrees or even the engine because its all aluminium, cooling fan comes at 95️
     
    #6 redprius2011, May 19, 2022
  7. StarCaller

    StarCaller Senior Member

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    "It can be estimated that the temperature at which gasoline engines start burning gases can reach 4,500 degrees Fahrenheit from a number of factors including the shape and load on the engine, the position of the engine, and the degree of rotation at the point of maximum output. The temperature can be as high as 6,000F in extreme conditions."
     
    #7 StarCaller, May 19, 2022
  8. Mt Bajwa

    Mt Bajwa New Member

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    Thanks everyone for the help. Really appreciate it. I took it to a mechanic. Turned out to be a clogged radiator grill. Its been a few days since it got fixed, tried it uphill on full load again. No overheating.
    Thanks again

    M2007J3SY ?
     
    #8 Mt Bajwa, May 19, 2022
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  9. ChapmanF

    ChapmanF Senior Member

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    Yes, the repair manual covers that. If the ECM is reporting a water pump failure, it will then do an abrupt engine shutdown if the temperature reaches 105 ℃.

    [​IMG]

    If there isn't a water pump problem on report, then nothing shuts down at that temperature. But get to 120 ℃ and you'll see the red thermometer light.
     
    #9 ChapmanF, May 19, 2022
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  10. Jacob Oversize Loads

    Jacob Oversize Loads New Member

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    I had Hybrid Pit do the work so I assume they got all the air out.
     
    #10 Jacob Oversize Loads, Jun 7, 2024
    2010moneypit? likes this.
  11. Wonder

    Wonder Member

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    When the water pump fins break off do they usually stay in the pump or can they get lodged in the system somewhere, causing to cut flow?
     
    #11 Wonder, Jun 17, 2024
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