Drain plug under 12 battery

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Hayward101, Jan 16, 2026 at 6:53 PM.

  1. Hayward101

    Hayward101 New Member

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    I just replaced the 12V battery in my 2009 Prius. There was several inches of water in the compartment. I drained it and am planning to seal where the hatchback meets the roof since I read that is often the culprit. I realized I accidentally left the drain plug out under the battery. I'm not the most handy and it was challenging for me to get the battery out, can I just buy a plug that can be stuck in from the underneath side or do I have to take the battery back out? What kind of plug would be best? Thanks for any help.
     
    #1 Hayward101, Jan 16, 2026 at 6:53 PM
  2. bisco

    bisco cookie crumbler

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    you could clean the area and try something like gorilla tape. don't leave it open though, mice like easy entries
     
    #2 bisco, Jan 16, 2026 at 8:25 PM
  3. Hayward101

    Hayward101 New Member

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    Ok thanks I'll put some over it in the meantime.
     
    #3 Hayward101, Jan 16, 2026 at 8:33 PM
  4. Tombukt2

    Tombukt2 Senior Member

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    No do not do that leave all the rubber plugs out for Christ's sake they're supposed to be removed at PDI they shouldn't be they're.. eve water should pass not stand. every where those plugs should be carefully removed . Unless you driving thru floods regularly. Even then water needs to pass.
     
    #4 Tombukt2, Jan 17, 2026 at 7:42 AM
  5. dolj

    dolj Senior Member

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    That can't be right. Every Prius (not to mention every other Toyota model) I have seen has all those plugs installed. I do not believe that every Toyota employee who is doing PDIs has misunderstood the factory process.

    Sure, leave it out temporarily if you have a leak to avoid standing water. However, once the leak is fixed and you no longer have water accumulating, then it is okay to reinstall the bung.
     
    #5 dolj, Jan 17, 2026 at 10:48 PM
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  6. Tombukt2

    Tombukt2 Senior Member

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    Water needs an interstate to travel thru you're vehicle . Not starting and Znd collect water shows up thru season changes etc leave em out in rear . Like you're boat wen emptying
     
    #6 Tombukt2, Jan 18, 2026 at 9:07 AM
  7. dolj

    dolj Senior Member

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    Another unintelligible reply, but no thanks.

    I have no interstate flowing through my car and I am not my vehicle, nor am I boat, whether emptying or not.

    I am quite satisfied with it all plugs installed as delivered.
     
    #7 dolj, Jan 18, 2026 at 11:08 AM
  8. bisco

    bisco cookie crumbler

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    won't vermin enter? the plugs that come out in port don't allow vermin in iirc
     
    #8 bisco, Jan 18, 2026 at 3:58 PM
  9. Tombukt2

    Tombukt2 Senior Member

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    See if you can find a PDI instruction guide I guess . I don't have it . I popped em out in 86 at Goodman Toyoda Raleigh NC. Celica 's Supra 's Previs ban etc
     
    #9 Tombukt2, Jan 18, 2026 at 8:19 PM
  10. Mendel Leisk

    Mendel Leisk MMX GEN III

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    I'm speculating as well, but think those plugs go in, and likely it's part of the stuff dealerships are supposed to do to earn their $1500~ for Pre-Delivery Inspection. My guess, and somewhat confirmed when I asked Service for a replacement plug, is that the holes are for some sort of restraining pins, used during shipping.

    The top-guns at Open Road Port Moody gave us our '10 with one plug missing, 40 psi in the temp spare (hey, at least it's got a spare), and a dead-as-a-doornail 12 volt battery (it had apparently been languishing in a back corner for 15 months). They also made a concerted effort to hide the 12 volt battery condition.

    Basically, that was the most I ever paid for a carwash... :cautious:
     
    #10 Mendel Leisk, Jan 19, 2026 at 2:36 PM
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