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Driving uphill Overheating issues

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Virgil Orly Dela Pena, Aug 11, 2024.

  1. Virgil Orly Dela Pena

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    I live in Vegas where temperatures often exceed 100°F. My 2012 Toyota Prius tends to overheat when driving uphill. The overheating light turns on, and my scanner shows the temperature rising to 220°F. I have the AC running and am driving at around 75 mph during this test.

    I replaced the water pump and cleaned the entire EGR and air intake system. This helped somewhat, but the temperature still reaches 214°F, and the overheating light continues to activate.

    Are there any aftermarket modifications I could consider? For example, an engine oil cooler, an all-aluminum and wider radiator, or adding a secondary radiator (such as a large transmission cooler)?
     
  2. Virgil Orly Dela Pena

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    [​IMG]
    [​IMG]

    This is what I think. The upper radiator hose is positioned in the middle of the radiator, which can be a design flaw. In this setup, the area where coolant flows quickly through the radiator is smaller compared to a traditional radiator where the upper hose is located at the top. In a traditional design, coolant enters the radiator from the top, ensuring it is evenly distributed across the entire surface, which improves cooling efficiency. However, with the hose in the middle, the flow may be less efficient, leading to potential cooling issues.
     

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  3. Virgil Orly Dela Pena

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    It doesn't even matter what I replace, even if this car was brand new. It would still overheat because it has a design flaw that causes inefficient cooling.
     
  4. AzusaPrius

    AzusaPrius Senior Member

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    Search "custom radiator project"

    You will see what I am doing.

    Funny you are a new member here and bringing this up.
     
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  5. Virgil Orly Dela Pena

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    I saw your post when I was doing my research. It's not for sale anywhere, nor does anyone sell something like it... :C
     
  6. Tombukt2

    Tombukt2 Senior Member

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    I wonder if anybody makes a double pass core that would fit this chassis so that the water makes two passes like the old VW radiators at the drag racers use with big block whatever they're running those things would cool anything all aluminum so on. I'm sure I have one in my Corolla on old Corolla not relevant here but I have aluminum desert cooler double pass radiator made by someone in China but apparently did a pretty good job because this thing is 25 years old and the car barely makes half gauge to the floor and running uphill of course it's not a hybrid either but I'm just wondering if anybody has retrofitted such a thing into a Prius it doesn't seem like it would be that hard and there is room I'm not sure what a z u s a is working on I guess I'll have to go take a look I'm not sure that any duct work or higher capacity fans are going to make any difference You're going 75 mph down the road that's 25 mi shy of 100 in any degree weather that ought to get you to regular operating temp not the necessarily the high end of operating ice temperature either although it's been years since I've lived in Arizona or out there in the west I really didn't have many overheating problems in any of my Toyotas but they were also not hybrids then.
     
  7. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    What’s the miles?
     
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  8. Virgil Orly Dela Pena

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    It has 104,000 miles. No check engine light. It only overheats under heavy stress. My 2014 toyota yaris can go up that freeway twice over and it would stay at optimal temperature.
     
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  9. ChapmanF

    ChapmanF Senior Member

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    If I remember right from the thread he started, the one Azusa's promoting is supposed to be double-pass.
     
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  10. Virgil Orly Dela Pena

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    Where did you buy that radiator? I see custom kit radiators on ebay where you weld the hose connections yourself.
    upload_2024-8-12_14-4-22.png
    Did you get it built by someone? If so, how much did it cost you? If you built it yourself, where did you buy the parts?
     

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  11. Tombukt2

    Tombukt2 Senior Member

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    Yes I need to go look at his business and see what he's got going on that just came to mind from the old VW radiator in the dragster days those VW scirocco and golf and rabbit radiators were double pass little things but cool like the Dickens.
     
  12. rjparker

    rjparker Tu Humilde Sirviente

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    I would look at the exhaust heat recirculation system. It may be stuck open allowing too much heat to pass the temp sensor which is hard wired to the combo meter.
    IMG_5929.jpeg

    You may be scanning the other temp sensor which is not getting hot enough to turn on the light by itself assuming the water pump is not coding.
    Exhaust Coolant  7C0 and Engine 7C4 Temp Sensors.jpeg
     
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  13. Tombukt2

    Tombukt2 Senior Member

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    Yes a Yaris or Corolla will have none of these issues like this I don't care how hot it is outside If it's that hot you'll be dying in short order also as well as the car. This is a this car thing the one you're sitting in the doing it.
     
  14. rjparker

    rjparker Tu Humilde Sirviente

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    We have 105f days and plenty of hills at high speeds up to 85mph legally. I monitor temp continously and have for years. No cooling issues and typically stays around 201f under those conditions.

    Prius P10 temp 8.jpeg

    You have a problem that needs repair with oem parts. Hopefully no head gasket or cooling system sealer was used.
     
  15. Virgil Orly Dela Pena

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    Okay, thats convincing. I’ll do a leak down test when I can to rule out minor headgasket issues that might be causing my overheating problem. If it passes the leak down test, i’ll replace the radiator and the fan assembly and see if that helps. I’ll be putting water wetter for the time being and hopefully it helps.
     
  16. Higgins909

    Higgins909 Member

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    Did you replace the thermostat too?

    I have a 2010 with 203k miles and oversized AT tires. I took my boat out the other day and it was at least high 90s and was fine. I think the highest I've ever seen was 214F~. 205F is pretty common when towing. Not towing 200 is probably the max.
     
  17. MAX2

    MAX2 Member

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    If you are driving at high speed and the coolant becomes overheated, please follow these steps.
    1. Carefully inspect the front end for coyotes and other roadside animals.
    [​IMG]

    2. Inspect the outside of the radiator for dirt and fluff.
    [​IMG]
    3. Unscrew the radiator mounts. Oh yes! Two radiators! Like a sandwich. And between the radiators there may also be a large layer of lint and dirt that requires cleaning.
    [​IMG]
    4.Rinse the radiator; fine sludge may accumulate inside and clog the internal radiator tubes.
    5. Replace the coolant pump. The design defect of the pump is that at high speeds and high temperatures, deformations or cracks appear in the plastic housing of the impeller drive. Its functionality is impaired. And it can jam against the body and not give the required number of revolutions for the intensive movement of coolant.
    [​IMG]
     
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  18. Virgil Orly Dela Pena

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    A few months ago, I took several steps to address cooling issues with my vehicle. I removed and cleaned the radiator, flushing it with tap water and power-washing it thoroughly. I also rebuilt the water pump by replacing the rotor with one I ordered from Amazon. Additionally, I rebuilt the radiator fans by cleaning the motor brushes and replaced the thermostat. When these efforts didn’t resolve the problem, I replaced the water pump (Aisin from Amazon, everything works after the install). Since I'm still encountering issues, I’m planning to conduct a leak-down test and have ordered a new radiator along with water wetter. If these measures don’t solve the issue, I’m ready to consider further modifications, such as installing an auxiliary pusher fan (which will probably just increase turbulence and not help during freeway speeds), fabricating a custom two-row radiator (this is what I think will fix my overheating issue), or modding the bumper for increase air flow (this is a cheap and a really good plan). If you have any additional tips or suggestions, I’d greatly appreciate your input. Thank you!

    upload_2024-8-16_14-14-54.png
    When I was rebuilding the water pump, I replaced the old rotor despite it not showing any scratches or visible damage upon inspection.
     
    #18 Virgil Orly Dela Pena, Aug 16, 2024
    Last edited: Aug 16, 2024
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  19. Virgil Orly Dela Pena

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    how do i delete this
     
  20. Tombukt2

    Tombukt2 Senior Member

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    It's not two row radiator that you want You want double pass like VW Passat and rabbits have that little tiny radiator up there that's aluminum double thickness but it's double pass look into it probably solve most of your cooling problems what you shouldn't really be having but out there where you say you are in your signature is quite hot literally unbearable how you do it I don't know how your car survives I have no clue