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Louder Engine Noise

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by renovator20, Jan 7, 2014.

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  1. renovator20

    renovator20 New Member

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    I have an 09 with 115000 miles. It is a great car. All I have done is fluid changes, 12v battery replacement, and tires. I have now noticed the engine/drivetrain is louder when driving at highway speeds. It is not an exhaust leak, just a louder droning sound. The car drives great, no change in mileage, no bearing noises, the car drives straight, Michelin defender tires now have 20,000 miles on them. Any ideas on what it might be? Thanks for any help with preventive maintenance.
     
    #1 renovator20, Jan 7, 2014
  2. jadziasman

    jadziasman Prius owner emeritus

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    Where are you located? The engine in my Gen II is loud when it's extremely cold out, like the last week here in District 6. The temperature has been less than 10°F for the past three days with a low temp of -15 °F last night.
     
    #2 jadziasman, Jan 7, 2014
  3. renovator20

    renovator20 New Member

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    #3 renovator20, Jan 7, 2014
  4. renovator20

    renovator20 New Member

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    Temperature has nothing to do with it. It got louder when I was driving near Taos (80's temp) and mainly running on the engine in the mountains. I commute 150 miles a day near Dallas (20-105 temp) so I am familiar with normal engine sounds.
     
    #4 renovator20, Jan 7, 2014
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

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    How do you know the louder droning sound is not caused by an exhaust leak? That and tire noise from a more aggressive tread pattern would be two likely causes which come to mind.
     
    #5 Patrick Wong, Jan 7, 2014
  6. frodoz737

    frodoz737 Top Wrench

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    Had your wheels balanced lately?
     
    #6 frodoz737, Jan 7, 2014
  7. renovator20

    renovator20 New Member

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    I agree with what you say. At idle, I can't hear an exhaust leak. I have looked over the exhaust mannifold and followed the exhaust with the engine running and I did not hear a leak or find cracks in the system. Maybe it is happening at higher rpm's and not audible at idle. I'm open to any suggestions. No exhaust smells noticed in the cabin either but that can be misleading.
     
    #7 renovator20, Jan 7, 2014
  8. renovator20

    renovator20 New Member

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    I get the tires rotated every 5000 miles with the oil change and there wasn't any change in sound. There is no vibration in the steering wheel or noticeable in the passenger compartment. I'll get the tires rotated again this week and inspected.
     
    #8 renovator20, Jan 7, 2014
  9. frodoz737

    frodoz737 Top Wrench

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    "Balanced"...Rotation is different.
     
    #9 frodoz737, Jan 7, 2014
  10. ursle

    ursle Gas miser

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    The exhaust has a doughnut at the header outlet, my muffler jobber implied that toyota's in general need a new "doughnut" now and then, mine was loud, then it wasn't.

    when the muffler rusted off, it was a"more" loud on corners and accelerating, easy fix.
     
    #10 ursle, Jan 7, 2014
  11. PriusGuy32

    PriusGuy32 Prius Driver Extraordinaire

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    Hmmm 115,000 miles and a droning noise at highway speeds? Sounds like a front wheel bearing to me.
     
    #11 PriusGuy32, Jan 7, 2014
  12. JC91006

    JC91006 Senior Member

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    I've noticed louder sounds on highway speeds before due to tires and possibly worn shocks. Try running your hands on the tire thread and see if it's flat and even. If you feel it bumpy and uneven, it could mean the shocks are no good and the tire is making the noise you are hearing.
     
    #12 JC91006, Jan 7, 2014
  13. Rich12

    Rich12 Member

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    150 mile a day commute? Well that's your problem right there... :)
     
    #13 Rich12, Jan 7, 2014
  14. renovator20

    renovator20 New Member

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    It is only 3 days a week and that is why I am driving a prius. The noise is more of an exhaust sound at higher speeds. I'll look closer at the exhaust donut and may replace it just to eliminate that. Thanks to all for your suggestions. Hopefully I'll get 300,000 miles out of my commuter. It is nearly a flat straight drive and all highway miles. I'm getting 45-50 mpg.
     
    #14 renovator20, Jan 8, 2014
  15. penfieldny

    penfieldny Junior Member

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    Hi Renovator, did you ever figure out what was causing the noise? Front wheel bearing, shocks, "doughnut" muffler thingie? My Prius started sounding this loud droning sound lately at 69K and it's really quite loud. I took it in for service and they said my car is fine, not to worry. Phooey. they didn't drive it at all. So I am taking it in again and asking them to drive with me to hear how really loud this is. I would appreciate your story!
     
    #15 penfieldny, Jul 19, 2015
  16. dolj

    dolj Senior Member

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    renovator20 was last seen here on PRIUSchat on Jan 15, 2014, a week or so after s/he joined and has only posted 6 times. I wouldn't hold my breath hoping to hear from her/him.
     
    #16 dolj, Jul 20, 2015
    PriusGuy32 likes this.
  17. bisco

    bisco cookie crumbler

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    tyres perhaps?
     
    #17 bisco, Jul 20, 2015
  18. wrothgar

    wrothgar Junior Member

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    I am having a similar louder than usual sound. It only happens when the gas engine kicks in. Looks to me like the exhaust pipe near the middle of car (don't know the correct term....but nearest the engine) is vibrating more than usual. The exhaust noise isn't as loud at the tail pipe as it is near the engine. It has just been a few days....at first sounded faint like the start of a wheel bearing going bad. 2008 prius with 130000 km.
     
    #18 wrothgar, Oct 30, 2015
  19. SWprius08

    SWprius08 SoCalprius

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    I had the defenders on on my 2008 base, size 205/60/15, it reduced my mpg to 38-43. I figured less mpg = more power needed hence more load on engine, i had similar high sound from engine, after about 8000 replaced the tires with ecopia 422 plus. Definitely huge improvement in engine sound and better mpg, ofcouse at the sacrifice of better handling and lower tire noise from the defenders. Btw i was able to sell the defenders at a very good price as well.
     
    #19 SWprius08, Dec 7, 2015
  20. edthefox5

    edthefox5 Senior Member

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    Yeah this car is all tire. I have found Kumho's to be the quietest tire so far.

    Btw, whats really strange about our cars is the difference in engine noise between the 2 fronts seats. For the first time in like 6 years my wife drove me somewhere in our 07 and I sat in the passenger seat. It sounded like the car had an exhaust leak the engine was so much louder
    from that seat. Alot more noises are heard in the passenger seat than in the drivers seat. Dramatic increase in noise over on that side.
    I never knew that.
     
    #20 edthefox5, Dec 8, 2015
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