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rattling sound comming from gas engine

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by BIGGDOGG, Apr 24, 2008.

  1. BIGGDOGG

    BIGGDOGG New Member

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    within the last week I have been noticing that when my gas engine kicks on it sounds like there is a metal rattling sound. It only has 5k miles on it but the gas engine sounds like it is an older car. I also have noticed a drop in MPG this week, from 52 to 48.9-49. I can't seem to get anybetter.
    Plus when the gas engine does kick on I notice that I cant't seem to get better than 30 mpg on the display, even when I am hardly pushing on the pedal and the gas engine is on.
    So my question is what could that sound be? because it makes my car sound like its 3 yrs old. Should I take it to the dealer to check it?
    I don't know anybody with a prius so I can't compare the sounds to theirs. I will be meeting with all you guys that are going to the HighLands Greenfest in 2 weeks though.
    Let me know.
    Thanks
     
    #1 BIGGDOGG, Apr 24, 2008
  2. qbee42

    qbee42 My other car is a boat

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    The Prius uses a high-compression (for gas) Atkinson cycle engine. Under some conditions it rattles a bit like a diesel. This is completely normal.

    Tom
     
    #2 qbee42, Apr 24, 2008
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Have you checked your engine oil level? Maybe the oil level is too low?
     
    #3 Patrick Wong, Apr 24, 2008
  4. BIGGDOGG

    BIGGDOGG New Member

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    I just never noticed it before I guess. I drove to MA 2 weeks ago and when I came back I noticed I needed to get my oil changed then the check engine light came on (for the oil change at 5k) and then I started to hear the noise. I got worried I guess because of the check engine light. I thought I might have pushed it too hard driving to MA and Back to NJ.
     
    #4 BIGGDOGG, Apr 24, 2008
  5. sendconroymail

    sendconroymail One Mean SOB

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    Maybe you purchased gas with a higher percentage of ethonal? This could hurt your mileage, its lower octane may also be causing your engine to ping, which is the sound you hear. But I'm just guessing.
     
    #5 sendconroymail, Apr 24, 2008
  6. BIGGDOGG

    BIGGDOGG New Member

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    I got my oil changed on monday. I still get the sound. I thought it would have gone away once the oil change but that hasn't happened. thats why I posted this now.
    I thought we were supposed to fill the tanks with regular gas not premium. And I don't think the gas station I fill at has 10% ethanol.
     
    #6 BIGGDOGG, Apr 24, 2008
  7. richard schumacher

    richard schumacher shortbus driver

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    Is the grille block still in place? If so have you been monitoring engine temps using an aftermarket tool? It would be a pity to save $10 worth of gas over the winter and then burn the valves...

    Ethanol actually has higher octane than gasoline, but that doesn't matter because E10 is blended to the octane rating stated on the pump; in other words "regular" has the same octane regardless of the ethanol content. If the engine really is pinging (that is, a knocking sound at high RPMs, and not just the usual brief Diesel-ish or run-on noises that Prius engines often make when shutting down) then it needs a repair, not different fuel.

    Just out of curiosity look for an ethanol sticker on the pump next time. E10 is very common now because it burns cleaner and so helps reduce air pollution.
     
    #7 richard schumacher, Apr 24, 2008
  8. BIGGDOGG

    BIGGDOGG New Member

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    I took the grille block off about a month ago. I guess I should call the dealership to check it then.
     
    #8 BIGGDOGG, Apr 24, 2008
  9. ad78

    ad78 New Member

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    mine does this also, but rattle will kick in if the engine will turn off. i guess it normal?
     
    #9 ad78, Apr 24, 2008
  10. BIGGDOGG

    BIGGDOGG New Member

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    Re: rattling sound coming from gas engine

    OK I got off the Phone with Amy from the Gold team at Toyota of Morristown (very Helpfull) and she told me the same thing Tom mentioned. That it was normal for the engine to make that sound since it is constantly turning on and off. So thank you huys for helping me out. And I will make sure to document this conversation between toyota and I just incase something terrible happens and they ask why I never brought it in to be checked. (knock on wood)
    Thanks again.
     
    #10 BIGGDOGG, Apr 24, 2008
  11. SpartanScott

    SpartanScott Michigan Member

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    One more comment... For the first minute the engine will run rich which is why you are seeing that it is hard to get above 30mpg during that time. Is this first minute or so after you start the car when you hear the rattling?
     
    #11 SpartanScott, Apr 24, 2008
  12. BIGGDOGG

    BIGGDOGG New Member

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    well during that first minute I do hear the rattle but I also hear it after driving for 15 minutes as well. When I accelerate and so on.
    But I do want to also say that this morning I got excelent gas mileage on the 20 min drive to work. first five min in the 25's and the last 15 min were all above 75mpg. It was a morning shock for me. Usually the first 5 min are in the low 20's then the rest are around the 50's. I love the Prius
     
    #12 BIGGDOGG, Apr 25, 2008
  13. apostasy10

    apostasy10 Junior Member

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    I'm wondering if this is the same rattling I'm hearing now. It mostly happens when first starting the car and driving through the city at low speeds (looking for a parking place--I'm in downtown philadelphia). I checked the oil when I first heard the sound, and that wasn't the problem. I might have to have this looked at the dealer before a big road trip this weekend.
     
    #13 apostasy10, Jun 26, 2008
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