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Loud engine

Discussion in 'Gen 2 Prius Technical Discussion' started by jbct, Jul 28, 2022.

  1. jbct

    jbct Junior Member

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    My 2008 Prius has 165,000 mi. A few months ago, prior to AC season, the engine started running a bit louder than it had been. I'm only getting 39 MPG. The following were checked and are good: tire pressure, oil level, coolant levels, air filter. I'm thinking maybe changing the transmission fluid or both coolants. Which one would be causing the louder-than-normal engine?
     
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  2. bisco

    bisco cookie crumbler

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    might be a leaky exhaust manifold
     
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  3. WilDavis

    WilDavis Senior Member

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    Back in January, some light-fingered, slimy shyte-for-brains stole ChugyPyg's catalytic-converter and the immediate effect on the noise-level of the running engine was quite noticeable. :eek: There was a rash of such crimes in this area back in January. It's 3 am. Do you know where your catalytic-converter is? :whistle::whistle::whistle:
     
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  4. PriusCamper

    PriusCamper Senior Member

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    How much louder? Like really loud? Or just sort of loud? And as per @bisco comment... Does it smell like an old 1970's car in the engine compartment when engine is running?
     
  5. bisco

    bisco cookie crumbler

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    if by 'louder than normal' you mean a little more rpm, could be the hybrid battery
     
  6. jbct

    jbct Junior Member

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    Alittle louder but noticeable from what it had been. Cat. converter is OK. No smell from the engine compartment. MPG down to 36.
     
  7. jbct

    jbct Junior Member

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    On the screen Energy Monitor, under Battery, the green bars are at about 90%. The blue bars at 80%. MPG are now down to 36.
     
  8. jbct

    jbct Junior Member

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    How can I check that?
     
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  9. monoshock

    monoshock Member

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    My guess is battery.
    Time for a NexCell kit.
     
  10. bisco

    bisco cookie crumbler

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    you would have to start with the manifold, feeling for escaping air, and work your way back to the muffler
     
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  11. mr_guy_mann

    mr_guy_mann Senior Member

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    Get a length of small hose (around 1/4" diameter, maybe 3 foot long). Hold one end in an ear while carefully moving the other end around exhaust system parts. When you get the hose near a leak, it will sound much louder . You need to keep the engine running. You can put the car in "maintenance mode", or try turning the heater up to hi-full hot.

    You need to safely raise and support the front of the car to be able to check everything- especially the spring loaded flex joint between the exhaust manifold and the catalytic converter. The "donut" gasket can wear and leak. If so, get a new one from Toyota- that fits and seals best.

    It can help to have a helper use a heavy leather glove to "cap" the end of the tailpipe and force more exhaust out of any leaks - do that for a few seconds at a time then pause so you don't get a burned hand.

    Posted via the PriusChat mobile app.
     
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  12. jbct

    jbct Junior Member

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    Update- I usually drive with the windows up hence the noise seemed to be coming from the engine. One day with the windows down I realized the noise was coming from underneath the car. In short, cat converter was on its way out. Replaced it. About $1000, ouch.
     
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  13. bisco

    bisco cookie crumbler

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    you can sell the old one for about the same price; win/win!
     
  14. edthefox5

    edthefox5 Senior Member

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    Surprised you found the OEM cat it’s been on back order for a long time last I heard.

    Hope you didn’t pay $1000 for an aftermarket $125 cat. Cost $80 to weld it up.
     
  15. lexidium

    lexidium Active Member

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    I just had noisy engine. It turned out I needed a new water pump.
     
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