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Replacing Coolant Flow Control Valve...again???

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by bybiggs, Dec 16, 2015.

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  1. bybiggs

    bybiggs New Member

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    Hi everyone! I took my 2009 Prius in to have the check engine light read and they came up with P1121 and recommended I have the coolant flow control valve replaced. I bought my prius used and noted that in the service history, the valve was replaced under warranty in Feb. of 2013, about 40,000 miles ago. I'm going to have the valve replaced, the prius and I are embarking on a 1500 mile journey in a week or so and I'd rather not take the risk of not replacing it. I've read quite a bit about it on the site, but still have been left with a question.

    My question for you all is, is it typical to have the valve replaced again? Is this something I should expect every once in a while?

    Thanks!
     
    #1 bybiggs, Dec 16, 2015
  2. bisco

    bisco cookie crumbler

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    how many miles on her, and how many on the newer valve?
     
    #2 bisco, Dec 16, 2015
  3. bybiggs

    bybiggs New Member

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    About 154k total, 40k since the valve replacement.
     
    #3 bybiggs, Dec 16, 2015
  4. bisco

    bisco cookie crumbler

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    that's pretty short time, but possibly they replaced with another defective valve.
     
    #4 bisco, Dec 16, 2015
  5. JC91006

    JC91006 Senior Member

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    I say just top off the coolant level if it's low and drive it on your trip. Check and make sure the heater works too.

    You don't want to mess with coolant before a trip, if it's not burped correctly (remove air from system after coolant change), you'll have overheating issues while on your trip.
     
    #5 JC91006, Dec 16, 2015
  6. andrewclaus

    andrewclaus Active Member

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    I agree--check the coolant, make sure your heater works, and take your trip. I recently drove a 3000 mile trip with a P1121 code. My heater worked throughout the trip--that would be the only real problem you might have. I also took along a cheap OBDII reader and checked daily to be sure no additional codes came up. I fixed it when I got home and the DIY project went very well--$70 part, $45 coolant, $25 Mini VCI to run the pump (though there's a clever paper clip hack on this site), a couple of hours.

    When you check the coolant, make sure you check at the (cold!) radiator cap, not the reservoir. You have to remove part of the plastic radiator cover to get to the cap--at least two of the six fasteners have to come out.

    I think I heard somewhere the valve was redesigned. If so, maybe you got one of the old ones as a replacement--bummer.
     
    #6 andrewclaus, Dec 16, 2015
    MidnightSun likes this.
  7. M in KC

    M in KC Active Member

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    Another 10,000 miles and you're due for a coolant change as well.
     
    #7 M in KC, Dec 17, 2015
  8. George Geisel

    George Geisel Junior Member

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    I changed mine at 100K , New coolant. Does the new valve cause the pump to run (thumping noise) when engine is off? Or is this a sign of another issue? I topped off the coolant in both reservoirs after a month. No codes 2008 Prius. I am former Toyota Mazda Tech. Retired for 15 years.
     
    #8 George Geisel, Dec 16, 2016
  9. andrewclaus

    andrewclaus Active Member

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    How long does it make the noise? The CHRS pump always runs when the car is powered off, for 10 seconds or so. (It also runs at every cold start.) There should be no thumping. Ideally it's a low hum, though sometimes mine squeals a bit. I wonder if you're getting some cavitation in the pump, though that shouldn't "thump." Did you run the pump a couple of times as part of the bleeding process? And have you checked the coolant level in the radiator neck?

    Sometimes the ABS accumulator runs when the car is off, and that's more like a rapid ratcheting noise, from the right side of the firewall.
     
    #9 andrewclaus, Dec 16, 2016
  10. George Geisel

    George Geisel Junior Member

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    Will try bleeding again, I did top of both levels after my question. But did not open the allen screw valve
     
    #10 George Geisel, Jan 6, 2017
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