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loud engine noise, ideas?

Discussion in 'Gen 2 Prius Technical Discussion' started by RyanG, Feb 1, 2018.

  1. RyanG

    RyanG Junior Member

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    Hi All,

    My '05 started making some pretty loud noise when the ICE is running. Wife had just gotten off the freeway when the noise started. Said the car would sputter when trying to start from a red light. When I first heard it, I thought it sounded like metal grinding of some kind, but after recording it and listening to the video it sounds like it could be air? One of the manifolds, maybe?

    Wait until about 10 seconds in for the engine to kick on...
     
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  2. JC91006

    JC91006 Senior Member

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    Sounds bad, how many miles? Any warning lights on the dash?
     
  3. RyanG

    RyanG Junior Member

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    No dash lights, 140k on the clock. OBD scan showed no faults.
     
  4. padroo

    padroo Senior Member

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    Take a long screwdriver and use it like a stethoscope along the top of the engine or wherever the you can get to and try to narrow the sound down.
     
  5. JC91006

    JC91006 Senior Member

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    Maybe it's coming from your water pump. Does it get louder if you point your camera to the water pump area? It's the area where the belt is connected to
     
  6. Lucifer

    Lucifer Senior Member

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    Toyota puts a donut between the block and exhaust manifold, my '06 needed a new one arounf 40,000
    I went aftermarket to get a better than oem part, the muffler went at 60,000 again aftermarket
     
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  7. RyanG

    RyanG Junior Member

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    So I got underneath and took another listen... sounds like it's coming from the transaxle. :(

    I've also observed that it sometimes rolls back a few degrees after it shuts off, and I hear the sound then as well. It would probably do it if I could roll it by hand.

     
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  8. JC91006

    JC91006 Senior Member

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    Ouch, if it's a whining sound, it's bad news.

    I had that on a 250k mile prius, needed a new transaxle.
     
  9. padroo

    padroo Senior Member

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    I would think if it was coming from the transaxle there would be metal shavings in the transmission fluid, I would drain the transmission.
     
  10. Aaron Vitolins

    Aaron Vitolins Senior Member

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    That sounds like a shot water pump. When was the water pump last replaced??
     
  11. RyanG

    RyanG Junior Member

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    I don't believe the water pump has been replaced. I haven't driven it since wife brought it home that day, but that would cause the car to stutter? I'll drive it down the street tomorrow and see what it does. I have an appointment set up for Monday but I like to be prepared...
     
  12. wjtracy

    wjtracy Senior Member

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    Does not sound like exhaust leak but a few similar threads people posting noise videos, the exhaust manifold had hole in it from rusting through. @Prius_Cub had that.
     
  13. edthefox5

    edthefox5 Senior Member

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    Reason there’s no codes is it’s strictly mechanical like a bad bearing.

    Trans might have fluid leak and is low or out of fluid primarily caused by bad inner cv joint seal wear. You may see it weeping where the inner cv joint axles enter.

    Sounds like a bad chain in the trans. Or a bad timing chain in the engine.

    How do you take care of maintence of the car. Who changed
    the oil and what kind of oil?

    But if you think it’s the trans pull the trans fluid. If it has metal on the magnet and fluid filled with particles it’s done.

    Reports of trans differential gear failures and thrust bearing failures
    But both somewhat rare and reflect poor fluid maintenance but I have never heard audio of the symptom.

    Go to lusciousgarage.com and search there repair blogs. They discuss various trans bearing failure.

    Mechanical trans failure is pretty rare on this site it’s a world class trans.
     
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  14. edthefox5

    edthefox5 Senior Member

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    Btw lots of used trans on eBay. Usually easier to pull the engine trans as a unit.
    Price on trans is $300-500 with fob and labor is $1000 but this is at an indie mechanic.
    If dealer does it the car will be totaled at $140 an hour labor forget it.
     
  15. RyanG

    RyanG Junior Member

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    Thanks for all the input everyone. I took it to an indie around the corner and they said it was a bearing. There are a lot in the salvage yards in the $200-$400 price range that aren't too far from me (w/ one year warranty). It would be $1,100 labor; so in the ball park.

    When I drove it there, the sound and resistance was only below 15 mph and it faded above that. Above 20 mph you wouldn't even know it there was a problem. Would a bearing do that? Either way, will just replace the whole thing.

    They also mentioned the brake actuator/pump was starting to go. Said the symptom is that it starts running a lot more often, which I have noticed. Not a cheap part if buying new but I will cross that bridge when I get there. I already replaced the HV battery with the guts from a 2013 a couple years ago, so that should be good for awhile. Leading to my question of, what's the next big thing to go? I'll keep it going as long as it makes sense.
     
  16. JC91006

    JC91006 Senior Member

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    I think the diagnoses of needing a new transaxle is probably correct. But the reason for it "a bearing problem", is probably not correct
     
  17. RyanG

    RyanG Junior Member

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    Yea.. I agree. If it were a bearing I would think it'd be speed independent. I'm not sure of the internals, but to me it sounds more like a torque converter or clutch type device, something with dynamics/engagement that are dependent upon rotational speed. Not sure it really change the prognosis, though. Either way, it has to come apart and that's the bulk of the expense.
     
  18. Aaron Vitolins

    Aaron Vitolins Senior Member

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    The prius doesn't have clutches or torque converters.
     
  19. RyanG

    RyanG Junior Member

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    Right, my point was that the sound went away above 15 MPH, as if it were something that had fully engaged by then. It's probably more related to that particular gear ratio. Which, now that I think of it, it probably is a bearing. One of the planetary gears or motors that slow down as the car speeds up under engine power. I'm sure by playing with the ratios we could figure out where it is. I don't think it makes the noise when the engine is off and moving under electric power only.

    Very helpful video on the internals (at least for me):
    This Is How Toyota Prius Gearbox Works - autoevolution

    Another cool video, which I'm sure isn't news to most on here:
     
    #19 RyanG, Feb 6, 2018
    Last edited: Feb 6, 2018
  20. edthefox5

    edthefox5 Senior Member

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    So they pulled the trans fluid? Or just said yup its the trans?

    Try the long screwdriver trick.Go to harbor Freight and get a long heavy duty screwsdriver and hold the metal end to the area of interest and put your ear on the handle end. Its the dixie cup on a string deal. Stethoscope is the right way but not everybody has one of those. You will clearly hear the area of noise.

    Try to isolate it It sure has a hollow bad chain sound to it. If it was the engine timing chain I suspect it would throw crankl/cam timing error most likely a missfire code.
    If its the trans chain there may not be a code as the timing relationship to final drive and mg is not monitored for phase. The mgs are monitored for phase for proper firing of the 3 phase but mechanically downstream post chain there is nothing.

    Its rare. I want to see trans fluid before I commit to new trans.Spend $50 and pull the fluid. Magnet should be bushy with debris.
    If pristine the trans is not your problem.
     
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