Change Coolant Control Valve? ...Moving to Subzero Temps

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by LEARNER, Jan 11, 2022.

  1. LEARNER

    LEARNER Junior Member

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    2004 Prius with 250K miles and thousands of ilde hours (Prius Camper).

    P1121 and Pending P1116, Living in Coastal Southeast now Heater works very well

    Have 3month or more work assignment in NW Iowa with subzero Temps

    Should I change the engine coolant control valve and the sensor it comes with because the subzero temps

    or can I let it ride like I have been doing?

    I believe I understand it has something to do with saving hot coolant to warm car on restart but could have that wrong or not exact.

    Is it critical to get that changed because of the subzero temps?

    Both coolants are not due to be changed for a while according to the manual.

    I'm just trying to nurse this Prius along until I get another but need it to start in the sub zero temps.

    Battery is in good shape according to Dr Prius and getting 43 mpg 70mph

    There are other expensive repairs like AC system but won't need where I'm going

    Not attached to the car as once was and will get a newer used Prius or RV later this year

    Need to make this decision in a day or so. Thanks in advance :)
     
  2. ChapmanF

    ChapmanF Senior Member

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    The valve's a hundred bucks brand new in a red Toyota box.

    I'd think it would be worth changing if you DIY. One less thing to worry about. That valve can end up impairing the cabin heat, which you'll probably want.

    If you can't DIY it and would be paying shop labor, maybe that changes the calculation some.
     
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  3. LEARNER

    LEARNER Junior Member

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    Thanks for the quick reply. Yes cabin is very good now but could change with subzero temps.

    Does it also have effect in making sure engine starts with warmed coolant especially in subzero temps?

    Cabin heat not working like it is now is enough to pay the $400 for hybrid mechanic to do it right.

    He said it would test coolants too to be sure they can handle subzero. Thanks :)
     
  4. nancytheprius

    nancytheprius Member

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    i am in iowa and mine has never been changed! no issues other than noisy startups and after turning off (might be pumps tho not sure if what you’re talking about is noisy on mine)

    Overall my point is i think you’ll be fine if you don’t change it. Summers get into 90s here and winters get subzero, so this shows how it can last thru the temp changes!

    For peace of mind tho it would definitely be reasonable replacing if you’ve got the time and money
     
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  5. LEARNER

    LEARNER Junior Member

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    Thanks for the reply. I don't notice any noisy startups or noisy shut downs in mine yet of course that could change in Iowa. Here the lowest temp so far is 28 but Feb gets colder.

    I assume you have the P1121 and possibly P1116. The light comes and goes on mine. Fortunetly for inspection it was off. I may hear some pump running for a while which may be filling or trying to fill the canister.

    This is a tough little car. I may go ahead and get it done and get a look over for the trip having a good hybrid mechanic here that talks to you (ex-Toyota)

    Need to get some warm boots so I don't get frostbite on my toes and waterproof. Have winter gear for all the rest that I would be sweating in here :) . Little dog will have to stay inside Jan and Feb.

    Small friendly town in Spencer IA. Thanks :)
     
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  6. jerrymildred

    jerrymildred Senior Member

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    I changed one on a 2006. It wasn't very hard, imho, and I think I only lost about a cup or so of coolant, iirc.
     
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  7. nancytheprius

    nancytheprius Member

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    no lights or codes on mine! might as well swap yours out if that’s what they correspond to

    also, nice abt spencer, iowa! i’ve applied to a job there before, but i’ve never been. hope you like it!
     
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  8. jerrymildred

    jerrymildred Senior Member

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    I mostly grew up in Sioux City. I think we got up to Spencer a time or two -- probably on our way to fishing at Spirit Lake.
     
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  9. LEARNER

    LEARNER Junior Member

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    Just got engine coolant valve replaced and noticed a boost in my mpg at 55 degrees F here from 39-40 mpg to close to 47mpg regular in city traffic (from cold start) which my 2004 Prius hasn't seen in a while. That's from the display. I'll have to do more extended tests when I have time and post to thread.
     
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