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thermostat location

Discussion in 'Gen 3 Prius Main Forum' started by franken1313, Apr 20, 2018.

  1. franken1313

    franken1313 Member

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    Where is the thermostat located?
     
  2. Raytheeagle

    Raytheeagle Senior Member

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    On the other side of the water pump;).

    Any reason you’ll be looking for the thermostat :whistle:?

    Keep us posted (y).
     
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  3. franken1313

    franken1313 Member

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    The car is overheatin & over heats when speeding up then seems to cool with the bypass. Also no heater
     
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  4. Raytheeagle

    Raytheeagle Senior Member

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    Coolant level is stable? How many miles on your Prius? The coolant level isn’t low?
     
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  5. franken1313

    franken1313 Member

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    There's a lot of coolant being spit into the resorvoir through the bypass hose. Over than that I don't think it's circulating. I just changed the water pump as well. I'm thinking the thermostat is stuck closed?
     
  6. Raytheeagle

    Raytheeagle Senior Member

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    You got access to Techstream? Any dash lights illuminated?

    I just did our water pump and thermostat on our 2010. Did the thermostat at the same time as the coolant was drained.

    You might have to go back in.

    What prompted the water pump change for your Prius? I did ours as a preventative maintenance item as it was in service for almost 9 years and 176 k miles.

    Good luck and keep us posted.
     
  7. franken1313

    franken1313 Member

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    High temp light plus check engine light. The temp is way high when engine is on. Temp will get to 270f and slowly go back down to 190f when on electric. No techstream
     
  8. Raytheeagle

    Raytheeagle Senior Member

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    With that temp, I’d be worried about the head gasket.

    Where are you located in the expanse of the USA? Might be able to point you toward a good shop for help.

    Definitely worth pulling the thermostat off and checking it’s functionali though.

    Good luck and keep us posted.
     
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  9. Mendel Leisk

    Mendel Leisk Senior Member

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    Here's some info from Repair Manual.
     

    Attached Files:

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  10. ChapmanF

    ChapmanF Senior Member

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    Trying to remember from when I changed my coolant ... I don't remember seeing any coolant even begin returning to the reservoir through the upper hose until it was warm enough to open the 'stat. So I'm not sure whether you'd be seeing that with the 'stat stuck closed. But I don't remember for sure.

    I wondered for a long time how a thermostat could even get stuck closed (nothing is ever really going to stop hot wax from expanding), but finally did find an answer: it has to be done in by severe overheating, originally caused by something else.

    So if you had severe overheating because of your old water pump, I guess it's plausible for the thermostat to have been taken with it.

    -Chap
     
  11. franken1313

    franken1313 Member

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    Changed the thermostat. Engine still over heats plus now the AC air is not cold
     
  12. Raytheeagle

    Raytheeagle Senior Member

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    What are the codes that are displayed on the dash?

    Did you check the old thermostat functionality?
     
  13. franken1313

    franken1313 Member

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    Check engine and temperature lights on dash. Am I suppose to see bubbles in the reservoir constantly?
     
  14. Raytheeagle

    Raytheeagle Senior Member

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    Can you take a video?

    Bubbling in the reservoir is not normal as that means the coolant is boiling or there is still air in the system.

    Where are you located?
     
  15. franken1313

    franken1313 Member

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    Am I suppose to see bubbles like turbulence not boiling bubbles
     
  16. Raytheeagle

    Raytheeagle Senior Member

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    I’ve not seen that on our 2010 with 177 k miles.

    I just recently swapped out the water pump and thermostat and have seen no difference in behavior.

    You’ll need a code reader to see what all the codes are.

    If you let us know what neck of the woods you are in, we might be able to direct you to a shop or someone with Techstream to help with troubleshooting.
     
  17. franken1313

    franken1313 Member

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    I will have techstream soon. Do you see small movement in your resovoir?
     
  18. Raytheeagle

    Raytheeagle Senior Member

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    The reservoir in a Gen3 is essentially an overflow tank, so there should be no movement.
     
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  19. franken1313

    franken1313 Member

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    Any thoughts on why I lost cold ac?
     
  20. Raytheeagle

    Raytheeagle Senior Member

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    Nope. The codes being read will help guide the next steps;).

    I’d check all connections to ensure that they are all snug in the area as you were around the ac system when accessing the water pump.

    How many miles on your Prius? Any accidents in its past?