1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Clean everything still knock when pressing on gas pedal

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Don Doan, May 26, 2022.

  1. Don Doan

    Don Doan New Member

    Joined:
    May 26, 2022
    5
    1
    0
    Location:
    USA
    Vehicle:
    2011 Prius
    Model:
    Four
    I have a gen 3 Prius 2011(250K miles). It violently rattles in the morning. Changed spark plugs. That fixed it. Continue to remove and clean intake manifold, fuel injectors, EGR valve and cooler, replaced PCV valve hoping the old engine knocking go away when pressing on the gas pedal but it still there. Wondering if anything else needed to be done or that the engine is too old?
     
  2. CR94

    CR94 Senior Member

    Joined:
    Dec 2, 2014
    2,642
    1,133
    0
    Location:
    Northwestern S.C.
    Vehicle:
    2011 Prius
    Model:
    Two
    No, it isn't "too old," but it's defective. Is coolant level dropping fast yet?
     
  3. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    107,571
    48,862
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    head gasket?
     
  4. Don Doan

    Don Doan New Member

    Joined:
    May 26, 2022
    5
    1
    0
    Location:
    USA
    Vehicle:
    2011 Prius
    Model:
    Four
    Coolant level is normal. Did a block test at the coolant tank, result negative. Engine does not rattle in the morning indicating the coolant is not gathered in the cylinder.
     
  5. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,474
    38,106
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    When did you do all this? Recently? Should have been done at least 150K back.
    Leak down test to confirm, but very likely head gasket has failed. How's the engine coolant level in reservoir?
     
  6. Don Doan

    Don Doan New Member

    Joined:
    May 26, 2022
    5
    1
    0
    Location:
    USA
    Vehicle:
    2011 Prius
    Model:
    Four
    I bought the car when it was at 245K miles, 7 months ago. I did those a week ago. The noise I heard was not loud, I think it was always there before, but since after the maintenance work, I did not put back the windshield wipers and the other parts attaching to the windshield which shields the noise that no longer heard after they were put back.

    I like to do the leak down test but don't know how. I recently bought the XTOOL A30D Bi-Directional Scanner but does not know how it can help perform the leak down test or even the compression test. That XTOOL does not come with a user manual. If I know how to get the cylinder to move to top of the compression cycle, then I can perform the compression test.
     
    #6 Don Doan, May 28, 2022
    Last edited: May 28, 2022
  7. Eddie25

    Eddie25 Active Member

    Joined:
    Dec 31, 2018
    315
    121
    0
    Location:
    IL
    Vehicle:
    2011 Prius
    Model:
    III
    You probably did, but make sure you got the little EGR ports on the intake manifold clean. I don't think it's in the popular EGR cleaning (edit: I mean intake manifold cleaning) video so it's possible people are missing it.
     
    #7 Eddie25, May 29, 2022
    Last edited: May 29, 2022
    bisco and Merkey like this.
  8. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,474
    38,106
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    These:

    upload_2022-5-29_8-37-40.png

    A long/skinny bristle brush with a shot of brake cleaner is good. If it's really clogged you may need to start with some sort of pick.
     
    Merkey likes this.
  9. Don Doan

    Don Doan New Member

    Joined:
    May 26, 2022
    5
    1
    0
    Location:
    USA
    Vehicle:
    2011 Prius
    Model:
    Four
    Thanks, I did clean those tiny ports very carefully with a long brush.
     
    Mendel Leisk likes this.
  10. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    107,571
    48,862
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
  11. johnHRP

    johnHRP Active Member

    Joined:
    Aug 6, 2014
    417
    130
    0
    Location:
    tally, fl
    Vehicle:
    2008 Prius
    Model:
    ----USA----
    If it rattles only after parking for few hours, probably head gasket leaks. If it rattle only on hard acceleration, it is not head gasket. Something else from the exhaust, timing chain tensioner. Worn vvti gear rattles only split of second and the timing chain guide could be more than 1 second rattle.
     
  12. Jon Vitrano

    Jon Vitrano Junior Member

    Joined:
    Apr 22, 2018
    16
    4
    0
    Location:
    New Hampshire
    Vehicle:
    2007 Prius
    Model:
    Base
    I have a similar problem with my 2014 Prius (225k miles). I had the EGR system cleans in Jan of this year, the transmission flushed and refilled as well at a hybrid shop. Recently, I am getting hard shakes from the engine when cold starting and sometimes when I stop and then accelerate to make the engine kick on. It will also do it while idling when the engine turns on to charge the battery.

    Also, had a cylinder misfire code popup and then clear itself out.

    Changed out the spark plugs but that didn’t fix the issue. Took it to my mechanic and he told me the engine isn’t rattling, it is coming from the transmission… he said my coolant levels don’t appear to be decreasing. I generally drive 100-200 miles a day and it drives fine otherwise. No issues when going higher speeds… is it the headgasket? What could be wrong with the transmission if that is what is rattling?
     
  13. ASRDogman

    ASRDogman Senior Member

    Joined:
    May 29, 2018
    5,837
    3,137
    0
    Location:
    Florida
    Vehicle:
    2010 Prius
    Model:
    Two
    Remove the spark plugs, shine a light into the cylinders. Do any look wet?
    If you rent a pressure tester you can put pressure on the coolant system and probably
    see coolant easing onto the piston.
    How does he know you aren't loosing coolant? Have you filled it? I won't take a lot to
    get the knock.
    You need to find someone who has experience working on a Prius.


     
  14. Eddie25

    Eddie25 Active Member

    Joined:
    Dec 31, 2018
    315
    121
    0
    Location:
    IL
    Vehicle:
    2011 Prius
    Model:
    III
    The rattling is the "planetary gearset" I believe. It is part of the transmission, but it's just a generic noise that you get when you have engine misfires on these cars. The "death rattle."

    It sounds like you have a blown head gasket, but the lack of coolant loss does give you hope. It could be anything that causes a misfire. Is it every cold start?

    Was the intake manifold ever cleaned?
     
  15. rjparker

    rjparker Tu Humilde Sirviente

    Joined:
    Jun 6, 2008
    7,475
    4,373
    7
    Location:
    Texas Hill Country
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    Generally gen3s allow coolant into the cylinder, particularly after a complete cool off. The coolant may or may not temporarily foul the plug. At first the engine heats up and stops the coolant loss before it is really noticeable except for startup rattling. The plug starts firing and the engine runs fine, typically for the rest of the day. People incorrectly think it is plugs, coils, injectors or clogged egr, even though it runs fine after a few seconds, wasting time and money.

    Occasionally the startup rattling and short duration coolant fouling may bend the connecting rod slightly. This is often unnoticed during a head gasket job, leading to a second failure a few miles later when the rod goes. Or the rattling is masked with a sealer allowing more time for the bent rod to break.

    The engine to transaxle damper is just that, a short term slippage mechanism when the engine rpms are not exactly matched by the electric motors through the planetary gears. This slippage is the startup rattling you hear. There is no mechanical disconnect like you get with a clutch or torque converter.
     
    Brian1954 likes this.
  16. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,474
    38,106
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Way too late.
     
  17. Jon Vitrano

    Jon Vitrano Junior Member

    Joined:
    Apr 22, 2018
    16
    4
    0
    Location:
    New Hampshire
    Vehicle:
    2007 Prius
    Model:
    Base
    better late than never.
     
    Mendel Leisk likes this.
  18. Jon Vitrano

    Jon Vitrano Junior Member

    Joined:
    Apr 22, 2018
    16
    4
    0
    Location:
    New Hampshire
    Vehicle:
    2007 Prius
    Model:
    Base
    apparently not every cold start. No issue on startup this morning…
     
  19. Jon Vitrano

    Jon Vitrano Junior Member

    Joined:
    Apr 22, 2018
    16
    4
    0
    Location:
    New Hampshire
    Vehicle:
    2007 Prius
    Model:
    Base
    Getting the headgasket checked at a hybrid shop today. What are the best options if it is the headgasket on a 2014 225k car? Gen 4 engine? Fix headgasket?
     
  20. Jon Vitrano

    Jon Vitrano Junior Member

    Joined:
    Apr 22, 2018
    16
    4
    0
    Location:
    New Hampshire
    Vehicle:
    2007 Prius
    Model:
    Base
    They did a combustion test on the coolant and it changed color indicating O2 in the coolant and a definite leak in the headgasket.