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Minor knocking sound towards rear

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by danmiller3, Apr 19, 2004.

  1. danmiller3

    danmiller3 Junior Member

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    Hi folks -
    Anyone ever hear a minor knocking like sound (hollow/knocking) towards the back rear, left of the car? It sounds like a mechanical knocking, and there isn't anything in the trunk to make noise.

    It happens when going over light bumps/city driving, but not on the highway.

    It's not driving me crazy, but thought I'd check.

    --Dan
     
  2. efusco

    efusco Moderator Emeritus
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    Just a possibility, but my license plate made quite a racket (rear worse than front) with bumps and closing the hatch. I got some weather stripping with adhesive and stuck it on the back of the plate, it's now much quieter.
     
  3. Bob Allen

    Bob Allen Captainbaba

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    Make sure everything in the trunk is buttoned down; the parts for the jack, etc. Check the spare tire too, there might be something loose down there.
     
  4. danmiller3

    danmiller3 Junior Member

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    You know, I totally forgot about that stuff. I'll check it out tonight. I think it might be the pull out trunk cover. I removed that this morning and will see how it is on the way home. If it's not that, I'll check the jack, spare tire and stuff.

    Thanks!

    --Dan
     
  5. efusco

    efusco Moderator Emeritus
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    Dan,
    I made an accidental discovery today while installing my solar charger. When you lift out the black tray, as you look down in the well area next to the spare, just to the right you'll see a pad of sound insulating material. When I tapped that area I could hear a distict abnormal rattle/buzz from beneath that area.

    I looked underneath, and what you see is the muffler, and a thin aluminum sheet of metal just above that. I shoved a piece of cloth b/w the bottom of the trunk/body and that sheet of aluminum...buzz gone. It took a couple of tries to get it placed correctly, and I don't know if it will stay there. I want to buy some of that expanding foam that turns hard that comes in a spray can and shoot some of that up there for a more permanant solution.

    I'll bet that this is part of your rattle too, if it isn't something else loose under there.
     
  6. smoore

    smoore New Member

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    You have a solar charger for your car, too? Way Cool!
     
  7. paulisme

    paulisme New Member

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    Solar charger, cool? Please. You should see the hamster wheel mod I'm putting in next week. It's freakin' awesome.
     
  8. efusco

    efusco Moderator Emeritus
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    I'ts not that cool. It's just for the 12v battery. The little solar charger I have has some alligator clips. I finally got around to clipping those onto the 12v today. The cord on the charger itself has a plug so you can use the alligator clips or the cigarette adapter. I decided to just use the alligator clips, leave the battery side of the plug accessible through one of the existing panels near the 12v and then I can plug in the solar panel charger when I need it (usually when leaving the car parked at the airport for long times while away on trips). I might also be able to get enough juice into the battery, if it dies on a sunny day, to get the Prius started in an emergency.

    This is the one I bought:

    http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...943333&tc=photo
     
  9. Frank Hudon

    Frank Hudon Senior Member

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    Say Evan, have you put a volt meter on it while it's in the sun and inside the car? I was wondering if the Low E glass had an effect on the output?
     
  10. efusco

    efusco Moderator Emeritus
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    You know, I hadn't, electronics stuff isn't may bad of tricks, but I do have a voltmeter and that's a darn good idea....I'll try that out tomorrow and see how it does.

    Does nobody care about my rattle discovery/cure? :(
     
  11. Frank Hudon

    Frank Hudon Senior Member

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    it's been catalogued here to have for future reference. Although I'm not sure about insulation behind a heat shield. You want some air flow to keep it from conducting heat to the body. Even insulation will conduct, yes I know not much but some will transfer thru.
     
  12. eak354

    eak354 Member

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    thanks for the link Evan. would the cigarette lighter adapter work in the Prius (i'm thinking maybe not), or should it only be hooked directly to the battery terminals like you do? that's a cool device!
     
  13. efusco

    efusco Moderator Emeritus
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    Coastal Dave documented in another thread how to make a jumper that will make the cigarette adapter on the dash 'active'--if you perform that modification then the cigarette adapter for the solar panel would work fine. But, currently, when the Prius is turned off the cigarette lighter/power points are not 'live' and the charger wouldn't work.

    Frank,
    RE: the insulation conducting. I'm sure you're right that it does conduct a bit, but realize that there is at least 1/4" space b/w the muffler and the little aluminium shield and almost zero space (and thus the rattle) b/w the shield and body. Also, there is nothing but a sound dappening pad and metal above that area. Even if a small amount of heat is transfered I don't think it could harm anything. And, as you say, I can't imagine that that foam stuff can conduct much heat.

    FWIW, even after I fixed that 'buzz', I've still got one by the passenger door....if I could get rid of that one I'd be a happy man.
    --evan
     
  14. lawrenceingalls

    lawrenceingalls New Member

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    They warned me about this at my dealership. Could be the little wheel lock bolt thing that's with your jack under the back storage area.
     
  15. danmiller3

    danmiller3 Junior Member

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    The dealer tightened everything up towards the back and it seems to be corrected. We'll see if it returns...

    The XMRadio was also installed without any trouble and I have to say it is fantastic!

    --Dan
     
  16. danmiller3

    danmiller3 Junior Member

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    Update on this...

    The dealer tightened some panels and everything was fine up until the last few days. The knocking noise is back and I am fairly certain it is coming from the rear wheel well area on the driver side. I noticed that some of the paneling in the trunk area on the driver side is loser than the passenger side and if you push on it it makes a thumping noise. The noise only occurs at low speeds, off highway, which I assume is because the roads are bumpier.

    The noise is driving me somewhat insane, but not horrible... :|