2010 Prius Radiator Coolant Fluid Recommendation and Questions

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by eirens, Oct 4, 2023.

  1. eirens

    eirens Junior Member

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    I want to top of my 2010 Prius Five's radiator fluid. It's just below the Low mark.

    I don't know what brand of fluid is already in there.

    Questions:
    1. What's the best fluid to use?
    2. Why is that the best fluid to use?
    3. Does it matter if what I put in (since I'm just topping it off) is a different fluid than what's already in there?
    I'm in Florida. So it's hot. No significant winters.

    Thanks!
     
    #1 eirens, Oct 4, 2023
  2. BiomedO1

    BiomedO1 Senior Member

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    When in doubt, top off with distilled water. Since no significant winters, dilution isn't an issue.
     
    #2 BiomedO1, Oct 4, 2023
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  3. eirens

    eirens Junior Member

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    Oh, thank you. I didn't know that was an option.

    Any suggestions for which fluid to use when I next flush it? It'd be nice to know if it matters much which fluid I use.
     
    #3 eirens, Oct 5, 2023
    Last edited: Oct 5, 2023
  4. Doug McC

    Doug McC Senior Member

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    The best source for type would be your owners manual (you can download one from the Toyota Owners website). Mixing types is definitely NOT a good idea. If you’re going to dilute it keep in mind that doing so will lower the boiling point which in hotter weather can be a concern and it dilutes the anti corrosion additive concentration.
    For more guidance on antifreeze and oil selection check out The Petroleum Institute of America website site.
     
    #4 Doug McC, Oct 5, 2023
  5. Mendel Leisk

    Mendel Leisk Senior Member

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    Toyota Tech Info site also has the manuals, in the "manuals" tab.

    On page 416 it's spec'd: Toyota Super Long Life Coolant, or [a long list of requirements for alternate, acceptable fluids]. I would just go with the Toyota fluid.

    What's the miles, btw?

    (Page 416 of that manual is attached)
     

    Attached Files:

    #5 Mendel Leisk, Oct 5, 2023
    Last edited: Oct 5, 2023
  6. ColoradoBoo

    ColoradoBoo Senior Member

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    While I shy away from buying Toyota OEM parts on Amazon (lots of fakes out there), I have been pleased with finding OEM Toyota coolant and transmission fluid from Toyota suppliers in the US....so check prices with them and, of course, research the source and read the reviews....don't want Chinese knock-off garbage.
     
    #6 ColoradoBoo, Oct 5, 2023
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  7. ASRDogman

    ASRDogman Senior Member

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    Why is it low??? Start of a failed head gasket?
    It is ALWAYS BEST to use the correct Toyota fluids for the coolants and transmission.
    Mixing coolants can cause it to become like jello. Which is NOT good and cause the engine
    to overheat, also NOT good.
    The cost difference is pennies.

     
    #7 ASRDogman, Oct 5, 2023
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  8. bdc101

    bdc101 Member

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    Honestly, just go to your local Toyota dealer and get a gallon of the standard pink coolant. It will be cheaper to pay your local dealer's markup than to pay a discount dealer's shipping costs. But if you are just topping off, then just use distilled water unless you need to put a ton of it in.
     
    #8 bdc101, Oct 5, 2023
  9. Mendel Leisk

    Mendel Leisk Senior Member

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    Regardless if you're just topping up or not, I'd buy a bottle, of Toyota Super Long Life Coolant*. It can be used eventually. If you tell the Toyota parts counter person what it's for, that's what they'll get you I'm sure. I've got two bottles kicking around, one never opened. They have no expiration date.
     
    #9 Mendel Leisk, Oct 5, 2023
  10. eirens

    eirens Junior Member

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    Thanks, everybody. This place is wonderful because of your work and care.

    137K miles, I think.

    I'll buy a bottle of the Toyota fluid at a dealership. I never cheap out on fluids. But for this I needed to know if mixing matters, etc. And I didn't have time to go to the dealership before a four-hour trip we're making. I checked the fluids for the trip. I don't usually check fluids (beyond brake) so it's possible this has been low for a very long time.

    I haven't decided if I'll top it off with distilled water. This is for a four-hour trip where my daughter will have the car and I won't be there. So we checked and saw it was below the low line in the reservoir. I don't check this fluid often. My mechanic checks when I bring it in. I only check brake fluid, it seems.

    Reservoir has lots of fluid in it. I don't think it's dangerously low. But it is below "L". What do you think? Pic attached. And here's a link to it:

    I don't have records of ever replacing the fluid during the time I've owned the car (since 2015). So I'll likely have the fluid replaced soon.
     

    Attached Files:

    #10 eirens, Oct 5, 2023
  11. eirens

    eirens Junior Member

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    Here's a pic. I do not have any idea how many months or years it took to get to that point. I wish I did. IMG_2373.png
     
    #11 eirens, Oct 5, 2023
  12. eirens

    eirens Junior Member

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    Thanks. I'll go straight to the dealer.
     
    #12 eirens, Oct 5, 2023
  13. eirens

    eirens Junior Member

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    Thanks. I'll go straight to the dealer.
    Thank you so much!

    137K miles or so.
     
    #12 eirens, Oct 5, 2023
  14. eirens

    eirens Junior Member

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    Thank you.
     
    #13 eirens, Oct 5, 2023
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