cold start knock/rattle fixed

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by BKS in IN, Jan 23, 2020.

  1. BKS in IN

    BKS in IN Junior Member

    Joined:
    Jan 23, 2020
    47
    17
    0
    Location:
    Indiana
    Vehicle:
    2013 Prius v wagon
    Model:
    Three
    Mendell, You are correct in a sense ...... the leak can be so small that just a small amount of antifreeze gets into the cylinder that it causes a no fire ...... but if the leak is bad enough that more antifreeze to gets into the cylinder, then it can cause "hydro lock" i believe its called, that then the rod gets bent or the motor will lock up. Im not sure if theres room for a teaspoon, a tablespoon, or a couple onces before hydro lock occurs, but 1/4 teaspoon of fluid would not cause it. There was about 1/2 -1 teaspoon in my cylinder when I pulled the head off, an amount that was questionable IMO.
     
    #101 BKS in IN, Feb 6, 2023
    Last edited: Feb 6, 2023
    Mendel Leisk likes this.
  2. Air_Boss

    Air_Boss Senior Member

    Joined:
    Jun 2, 2012
    3,726
    994
    0
    Location:
    New Yawk
    Vehicle:
    2012 Prius v wagon
    Model:
    Five
    Classic hydrolock
     
  3. rjparker

    rjparker Tu Humilde Sirviente

    Joined:
    Jun 6, 2008
    5,890
    3,356
    2
    Location:
    Texas Hill Country
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    The hydrolock failure is often delayed. First a minor bend of the rod. The attached piston still functions. Over a period of time metal fatigue and uneven cylinder wall occurs leading to a complete failure. Often with holes in the block. When the knocking and severe rattling starts it is time to move straight to head gasket diagnosis and repair. Not weeks of delay caused by incorrect dealer and forum diagnostics leading to egr cleanings, catch cans, plugs, coils, injectors and sealers. Most typically providing a temporary reprieve and happy face.

    Low tension piston rings are the root cause and were epidemic in many models of the era. They allow excessive blowby which feed the egr and pcv systems. At some point they are obvious and create excessive oil consumption. Toyota acknowledged this problem early, repaired many free and updated new production by mid 2014.

    Egr design and carbon buildup in gen3 hybrids are symptoms and not the root cause. Toyota has never acknowledged the egr as a problem other than software upgrades for gen3. The Corollas of the time using a 1.8 and egr don't exhibit unusual numbers of head gasket failures.

    Thermal cycling of the gen3s makes a difference. These engines can temperature cycle the block and cylinders by 50f.

    Toyota's gen4 redesign was implemented by 2016. Better pistons and rings. Far different thermal management of the cylinder walls including a special insulator. Improved cooling channels around the cylinders and heads. The egr was rerouted downstream of the catalytic converter to reduced intake hydrocarbons along with increased egr size. Intake and pcv design changes to reduce liquids pooling in the intake while improving combustion.

    Sure egrs are a contributor but many with frequent egr cleaning still experience failed head gaskets. Sure any engine that overheats can blow a head gasket. But the Prius gen3 was a dramatic change to gain mpg but resulted in many issues (not all engine) which were not adequately resolved until gen4.

    These days the best solution for a high mileage engine failure is a rebuilt engine. A used engine if you want to flip it.

    We now have gen5 where mpg increases are slight but power improvements are huge.
     

    Attached Files:

    #103 rjparker, Feb 6, 2023
    Last edited: Feb 6, 2023
  4. Mendel Leisk

    Mendel Leisk Patron saint of newly poured sidewalks

    Joined:
    Oct 17, 2010
    50,631
    35,977
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    So if you've got no oil consumption the EGR doesn't clog?

    To be fair I think it's a symphony of screw ups. But my money's on the EGR design.

    I can't see a design being a symptom.
     
  5. CR94

    CR94 Senior Member

    Joined:
    Dec 2, 2014
    2,387
    1,025
    0
    Location:
    Northwestern S.C.
    Vehicle:
    2011 Prius
    Model:
    Two
    Did they not use the same rings? My niece has a 2013 Corolla.
     
  6. BKS in IN

    BKS in IN Junior Member

    Joined:
    Jan 23, 2020
    47
    17
    0
    Location:
    Indiana
    Vehicle:
    2013 Prius v wagon
    Model:
    Three
    rjparker, wow, thats alot of new information that i havent seen till now. I will agree with all you say, I take it you are in the automotive industry? anyhow, you are saying what i was trying to say, if you have the cold start hard knock problem, it is a head gasket leaking antifreeze into the cylinder(s) and if you address it soon enough to avoid a bent rod, then all should be good.
     
  7. BKS in IN

    BKS in IN Junior Member

    Joined:
    Jan 23, 2020
    47
    17
    0
    Location:
    Indiana
    Vehicle:
    2013 Prius v wagon
    Model:
    Three
    Mendell, oil consumption does not need to be present for the EGR clog to happen. I never had to add any oil to my Prius in between oil changes.
     
    Mendel Leisk likes this.
  8. CR94

    CR94 Senior Member

    Joined:
    Dec 2, 2014
    2,387
    1,025
    0
    Location:
    Northwestern S.C.
    Vehicle:
    2011 Prius
    Model:
    Two
    But how much did the level drop between your oil changes, and how far apart were the changes?
     
  9. BKS in IN

    BKS in IN Junior Member

    Joined:
    Jan 23, 2020
    47
    17
    0
    Location:
    Indiana
    Vehicle:
    2013 Prius v wagon
    Model:
    Three
    rjparker, "2008 Prius 3 (sold, sometimes I wish I had it back)" ........... just curious, did this generation of prius have any issues? if not, why would toyota change design from the old design?
     
  10. BKS in IN

    BKS in IN Junior Member

    Joined:
    Jan 23, 2020
    47
    17
    0
    Location:
    Indiana
    Vehicle:
    2013 Prius v wagon
    Model:
    Three
    CR94, changed oil every 10000 miles per toyota's recommendations. I live in a small town, no big city driving at all. All my vehicles that have the oil change "life" have gone the mileage that the manufacturer says to change the oil. oil consumption may have been 1/2 qt.
     
    Mendel Leisk likes this.
  11. rjparker

    rjparker Tu Humilde Sirviente

    Joined:
    Jun 6, 2008
    5,890
    3,356
    2
    Location:
    Texas Hill Country
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    Corolla 09-11 had low tension and became oil burners.

    Gen2s had a convoluted coolant strategy and some burn oil but they had no egr. I think gen2 was a better car overall especially for reliability. HV batteries in both gens created a new small business opportunity, many who have proven to be scammers or a waste of money.
     
  12. jzchen

    jzchen Newbie!

    Joined:
    Apr 9, 2012
    2,979
    904
    0
    Location:
    Arcadia, CA
    Vehicle:
    2012 Prius v wagon
    Model:
    Five
    One slight correction: Toyota has a revised EGR Valve for cold soak (extreme cold) cold start issue, although I have since lost the TS-B and part #s.

    I’m probably the only one with the flash that has the older/original EGR valve…
     
Loading...