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Strange knocking noise - I don't belive it is the ICE - Help Please :)

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Cooker, May 5, 2014.

  1. Cooker

    Cooker Junior Member

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    I recently bought a 2007 Prius that is making a rather loud knocking noise that has me a bit perplexed. I know the noise is not normal as my 2005 does not do this.

    The noise only happens when the ICE is running and the car is in drive

    If the car is in park and you rev up the ICE the noise is not present. With that said I do not think the noise is isolated to something in the ICE as I think it would be present when reving the engine in park.

    However is you put the car in drive and step on the brake (to keep the car stationary) while lightly reving the ICE the noise is present.

    The noise is present every time the car is in drive and you accelerating, even with the lightest of throttle.

    It does not need to be under excessive load and with that said I am certain it is not spark knock/per-detonation of the fuel nor does it have the "pinging" sound like a spark knock.

    If while driving down the road and the ICE shutdown down while driving at lower speeds the noise disappears. When the ICE starts back up the noise reappears.

    Sorry for the long description but I am trying to be as descriptive as possible as I would like to sort this out.

    Any suggestions? I have read some info about a "hybrid coupler" which might be the culprit?

    Thank you very much for your time.
     
    #1 Cooker, May 5, 2014
  2. Cooker

    Cooker Junior Member

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    I'm sorry for the triple post. I did not get notification the thread posted so I tried to post it again.

    If a moderator could please delete two of these thread I would appreciate it.
     
    #2 Cooker, May 5, 2014
  3. JC91006

    JC91006 Senior Member

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    I had s similar issue that resulted in everyone telling me it's my valves. Too much clearance

    SM-N900P ?
     
    #3 JC91006, May 5, 2014
  4. bisco

    bisco cookie crumbler

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    how many miles on her?
     
    #4 bisco, May 5, 2014
  5. JC91006

    JC91006 Senior Member

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    #5 JC91006, May 5, 2014
  6. edthefox5

    edthefox5 Senior Member

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    Maybe very beginning of rod bearing failure. Few posts of those on high mileage or ran low oil/empty on oil.

    What is the miles on the car and can you tell if poorly maintained engine oil wise? Typically if over 125K miles the ICE will eat oil. Most owners refuse to check the oil ever and unaware of this oil issue and will drive till the oil pressure light illuminates. Usually this is too late damage done usually the rod bearings.

    I suggest you go to Toyota.com/owners and join and post the vin. If any dealer servicing or dealer advising it will show up on that site.
    Lots of new owners of used prius discovered bad news on that site where the dealer gave the car a death certificate with repairs in the $XXXX. region and the owner traded it in on new. Out to auction it goes.
     
    #6 edthefox5, May 5, 2014
  7. Cooker

    Cooker Junior Member

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    Thanks for the replies.

    227,000 Miles on the car.

    I looked at the service history and the previous owner appears to been on top of servicing the car and that was one of the main reasons I purchased it.

    If it were rod bearings or valves I would certainly expect the noise to be present while reving the engine in neutral. I don't think this noise is solely isolated to the engine itself.

    The noise is not like any of the noises in the link.

    Also, the noise is present regardless of whether the engine is warm or cold.
     
    #7 Cooker, May 5, 2014
  8. JC91006

    JC91006 Senior Member

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    If you are only hearing this noise when the engine is in Drive and not in park, it may be a transaxle problem. But I can't remember ever reading a transaxle knocking sound.

    Can you put your car in inspection mode and stand in front of your car and see if you can hear the sound while the car idles?

    To get into inspection mode:

    Prius - How to enter Inspection Mode - TeacherTube
     
    #8 JC91006, May 5, 2014
  9. edthefox5

    edthefox5 Senior Member

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    No knock just reving engine. That's pretty common. Early rod bearing failure sounds will be exacerbated under load.
    Valves don't knock. Top end motor noise is easy to hear and pin point. The no noise or low noise knock is why people continue to drive the car and eventually it will throw that rod through the block. Seen a few of those on this site.

    If you have someone competent to help you get the car up on ramps. Have someone with parking brake on and standing on the brakes put it in drive and give it some gas while you listen under the motor.

    Only take 3 seconds. It will be very loud knocking under there.
     
    #9 edthefox5, May 5, 2014
  10. Former Member 68813

    Former Member 68813 Senior Member

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    Diagnosing source of knocking over the internet is not easy job.
    Read this interesting story on knocking prius:


    http://www.aecs.net/techniek2012/March%20prius.pdf
     
    #10 Former Member 68813, May 5, 2014
  11. Cooker

    Cooker Junior Member

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    I will give this a try tomorrow when I get a moment.

    If in fact it is the rod bearings it does not appear that the design of the engine will allow for replacement of the bearings while the engine is still in the car. It this correct?
     
    #11 Cooker, May 6, 2014
  12. edthefox5

    edthefox5 Senior Member

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    Don't recall anyone rebuilding lower motor on this site although I'm sure it's very possible.
    It's got alot of miles. You never know how hard its been driven.

    Used G2 motors are quite plentiful. Lots on eBay and pretty cheap.
     
    #12 edthefox5, May 6, 2014
  13. Cooker

    Cooker Junior Member

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    I have to pull the engine to replace the rod bearings I will replace it with a lower mileage engine as they can be purchased so inexpensively.

    If removing the oil pan when the engine is still in the car I would rather replace the rod bearings while the engine is still in the vehicle.
     
    #13 Cooker, May 7, 2014
  14. Cooker

    Cooker Junior Member

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    The car started making a different type of noise over the weekend. A much more severe and concerning type of noise. I dropped it off at the Toyota dealer and got the bad news. The car needs an engine. Now I'm on to researching engine replacement :(

    I might start another thread with these questions but I thought I would throw them here too:
    -Anybody know of any shops in or near Grand Rapids, MI that will R&R and engine at a reasonable cost?
    -I am a fairly competent mechanic and I think I could tackle a project like this myself but as I understand it the engine is best to remove from the bottom of the car and I don't have a way to get the car high enough to get the engine out the bottom. Can the engine come out of the top too?
     
    #14 Cooker, May 27, 2014
  15. Jeremy Gill

    Jeremy Gill New Member

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    Gaday guys and gals.
    I recently bought a 2006 Prius for $500 from a seller who had bought a new prius due to mechanical issues with the old one.
    It has a top end noise which sounds like a tap tap tap from the cam train area. I took the chance thinking at the worst case scenario, i could put a new engine in for a another $500 with a 4 month warranty from a local wrecker.
    I put a ODB2 analyser on the car but it showed no fault codes. all systems run well apart from the engine noise.
    I used a large screwdriver to my ear to localise the area of the most noise, and it seems to be coming from the number 4 piston area at the back of the cam train.
    i am going to remove the rocker cover and do a inspection on the cam trains to see if anything obvious appears.
    Before you say it ! the car has been to the toyota dealer for anaylasis and they told the previous owner the engine was stuffed without giving her a detailed explanation and tried to sell her a new car. Honesty is not the path that this dealership follows.
    And on top of this, they dissabled the engine by pulling a few relays so it no longer ran and faults showed on the display screen. I replaced these relays and got the car running again.
    No one seems to investigate this issue which has been common with many cars before from what ive read so far, so i would like to know if anyone has further information about this problem.
    Im not worried about replacing the engine. just would like to know why and what is going on.
    Just because i like to know and investigate to gain knowledge before saying screw it, lets take the easy option.
    Kind regards
    Jeremy
     
    #15 Jeremy Gill, Jul 30, 2018
  16. edthefox5

    edthefox5 Senior Member

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    Start a fresh thread instead of tagging a 4 year old thread you will get more hits.
     
    #16 edthefox5, Jul 30, 2018
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