Bad terribly annoying no good three way coolant valves

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Deveak, Jun 15, 2025 at 10:33 PM.

  1. Deveak

    Deveak New Member

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    Vehicle:
    2008 Prius
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    ----USA----
    I use my Prius for gig work so it gets a lot of miles. Recently I got the p1121 code and ignored it because I read on various forums it wasn’t important and most likely a stuck valve. A few weeks later it turned into p1122 and a red triangle. Luckily I just set out and was only a few miles from home. I drove back slow, mostly in EV and downhill.
    Turned out the three way valve internally failed at the rotary seal and leaked all of my coolant out. Many a hot and sweaty hour later I replaced it with a 4 season third party valve and it’s working again but I can occasionally hear the sound of it hunting from
    The sensor being out of sync or whatever you want to call it. Is it a bad valve or just not very good? If it is a failing part, would it fail catastrophically like last time or can I just keep driving it with the code if it pops up again? I need it for work.
     
  2. bisco

    bisco cookie crumbler

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    Plug-in Base
    there's no way to know, but we have seen a lot of problems with aftermarket (cheap chinese) counterfeit parts. recommendation here is to buy oem from online toyota dealer of brick and mortar.
     
  3. Tombukt2

    Tombukt2 Senior Member

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    Base
    I have one gutted right now I want to set it in the Midway point so all three ports just stay open pull out motor or driver gear. So motors on nothing moving. Close up install . See what goes down