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Hybrid battery fan during cold weather

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by sophie999, Dec 31, 2020.

  1. sophie999

    sophie999 Junior Member

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    Greetings,

    I have 2010 prius II, about 160K mi, only owner, all regular maintenance by the dealer.
    I have read several threads about battery fan noise during hot weather. But I have just noted noise that sounds like fan from the battery compartment. It is cold now, less than 32F. The noise starts at the beginning of the trip, stops temporarily when the ICE shuts down during the red light stops, and disappears altogether after 5-7 min of driving.
    I have not heard it before (at least I think so). Started a week ago when the temp dropped. I lived in the same area since the initial purchase. The temps here are usually below 20 in the winter, so nothing unusual. Should I be concerned?
    Thanks much.
     
  2. StarCaller

    StarCaller Senior Member

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    clean it /
     
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  3. rjparker

    rjparker Tu Humilde Sirviente

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    Either the fan or the fuel pump
     
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  4. Higgins909

    Higgins909 Member

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    I've got 183k on my 2010. I think everything is original for now. I took apart everything to clean the battery fan and it wasn't even that bad. I think I broke something trying to take it apart. Screwed up my rear seat, so good luck to anyone that sits back there, the whole thing might slide with you on a hard stop. I'm the 2nd+ owner. Right now it's so cold that I haven't heard the fan in a while. I used to be able to hear it in spring/fall when the temps were right and I didn't have to blast the A/C. When trying to do 40 in ev and using ev to 26mph, I can hear the fan spool up.

    I think I seen, even when you can hear the fan, it's only at about 20% use. Hope it's just because it's cold that it's making noise and it will go away when it warms up. Weather it's the fuel pump or battery fan. Also don't be running the fuel too low. I used to run it until the was 1 gallon left all the time.
     
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  5. Higgins909

    Higgins909 Member

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    Just noticed you're the only owner. If you have dogs back there all the time or people with long hair, then you might need to clean it. If no one is ever back there, it is most likely fine.
     
  6. Mendel Leisk

    Mendel Leisk Senior Member

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    @Higgins909 did you pull off the rear seat cushion? That’s really not necessary: there’s ONE bolt you need to access, which can be done by just pushing apart the seat bottom and back, reaching through with your hands and a ratchet extension.

    @NutzAboutBolts video shows the seat being pulled; I really wish they’d put a disclaimer in the video about that,
     
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  7. sophie999

    sophie999 Junior Member

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    I have no dogs. Very rarely do I have someone sit there. I will ask the dealership to look at it at the next service. I do not run low on gas, especially when cold.
    Anything I can do for the fuel pump? Any additive to clean it?
    Thanks
     
  8. Mendel Leisk

    Mendel Leisk Senior Member

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    Could be hybrid battery going too?
     
  9. Higgins909

    Higgins909 Member

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    Sophie999, if you want to spend money to have them look at it, go ahead, but me personally, I would live with it. Until it was obvious something was wrong. Could be flushing money down the drain. Could be nothing and go away when it warms up. Hopefully it is not the battery making that noise. I think stuff would be going down if it was and you would smell it.

    Yeah, I took it off. One side came up easily and the other was very stubborn. I think it was already torn, but I tore it more. Like part of the wireframe for the seat got ripped away a bit. I also broke both of the white plastic things. Put them back in. I think there was some white clip for the battery fan's wire harness that was also broken.

    I think I tried to do it without removing it and I couldn't see how it was possible.
     
  10. Mendel Leisk

    Mendel Leisk Senior Member

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    Directly below the hybrid battery fan inlet grill, push down on back edge of seat cushion, and up on seat back bottom edge, creating an opening. Shine a light through to see the single 12 mm (socket size) bolt. Remove it with ratchet wrench with extension. Hold it with you fingers as it comes out, don’t drop it.
    That’s it. Install is the reverse.
     
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