2010-2012 Head Gasket failure analysis

Discussion in 'Gen 3 Prius Technical Discussion' started by ToyXW, Apr 9, 2018.

  1. ToyXW

    ToyXW New Member

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    Cliff notes: I conclude that Prius headgasket failures are largely the result of a material defect affecting the coating of headgaskets installed on some 2010-2012 Priuses and some 2012 Prius Vs.

    Discussion: There are a couple different types of headgasket failures. In the 1980s and 1990s, what we usually saw was gasket material failing as a result of aluminum heads expanding at a different rate than iron blocks. This created abrasion which accelerated gasket deterioration. At the same time, we had lots of manufacturers and shops switching to extended and long life coolants which could create acidic mixes if the old coolant was not totally flushed. These problems were generally fixed by redesigning headgaskets, using tighter tolerances in the assembly process (smoother surface finishes on the block & head), and sticking with 1 type of quality coolant (e.g. Toyota Red).

    In the hot rodding world, you often blow a head gasket when cylinder pressures run too high. The head literally lifts off the deck and caustic combustion gases start eating away at the gasket. This is addressed by either lowering cylinder pressure -- less power, less heat, or less knock (higher octance, less timing, and/or more fuel) -- or by tightening the head down even more (upgrading head bolts/studs).

    When you look at a failed gasket, a head lift or knock-induced failure generally happens at the thin strip of gasket between cylinders. This is the part of the head that is farthest from the head bolts and most likely to flex. ( Cylinder Head Lift | Technical Bulletins | Fel-Pro Gaskets )

    DXTA posted a picture of this type of failure on a Corolla, right between his fingers:
    [​IMG]

    This can happen on any car if you have it run hot or knock.

    But the failures Leeb18c and I had were different:
    LeeB18c
    [​IMG]

    Mine:
    20180409_134613-1-1.jpg

    Notice that the gasket coating on Lee's is totally eaten away where the coolant comes in contact with the gasket -- all around the entire gasket. On mine is is eaten away almost completely on half of cylinder 1, but still intact for most of the gasket. Unlike Lees, mine did eat through the combustion ring into the cylinder which caused white smoke & the (not so) sweet smell of coolant being burned. I did have a start-up knock for about a week which probably pushed my gasket the rest of the way into the grave (I replaced coils, plugs, boots, water pump, thermostat, and cleaned & flow tested my injectors. Everything tested/looked fine, except my EGR cooler was partially blocked).

    Hypothesis: Old coolant, which tends to get acidic, eats away at a less than optimal gasket coating over time and leads to a failure. Knocks or misfires can help speed this up, but aren't the cause.

    As evidence of my hypothesis, take a look at the original Toyota part numbers for head gaskets:

    2010-2012 Prius, 2012 Prius V: 11115-37051
    2012-2015 Prius, Prius V: 11115-37060
    2015+ Prius: 11115-37061

    37060 replaced 37051, and 37061 now replaces both. Sometimes these part number changes just happen without any design changes, but since gasket failures on 2013+ cars are very rare (and no changes were made to cylinder head torque), I believe the coating was improved to be more durable. Additionally, the jump in numbers from 37051 to 37060 to me suggests a design change as opposed to an incremental change like 37060 to 37061.

    If this is true, owners of 2010-2012 cars may be able to mitigate the risk of head gasket failure by changing coolant more often (mine was not changed for 7 years & 120,000 miles - gasket failed at 130,000). And if they replace their head gasket with a new version, they may not have issues again (I have yet to hear of a 2nd blown gasket, and neither have a couple of hybrid shops I polled). For best results, combine with EGR (and manifold/TB) cleaning at regular intervals.


    Additional questions: Does more electrical current flow through the engine block/head of a hybrid vehicle? If so, does current flow accelerate coolant degradation?
     
    #1 ToyXW, Apr 9, 2018
    Last edited: Apr 9, 2018
  2. b100

    b100 Member

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    This seems legit
     
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  3. taxibuddy

    taxibuddy Junior Member

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    No.

    Thanks for the post. I look forward to the resulting discussion.
     
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  4. farmecologist

    farmecologist Senior Member

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    Great analysis!
     
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  5. Jayw13702

    Jayw13702 Active Member

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    Some great points there.

    I have to ask what’s to difference between the Toyota red coolant and standard red coolant?


    2010 Gen 3
     
  6. ToyXW

    ToyXW New Member

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    To be honest, I haven't kept up with the latest and greatest coolants of the last decade. In the 90s and early 00s, Toyota Red was about as good as you could buy for a Toyota, widely available, and not terribly expensive. Other long life coolants of that period sometimes caused water pump problems. There is a website for oil/fluid geeks -- bobistheoilguy -- that probably has a thread somewhere breaking down the different ingredients in each coolant and their pros/cons.
     
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  7. emendia

    emendia Junior Member

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    Interesting and useful. We have a 2012 Prius C that I now worry about. I recently had our 2007 Prius need new fuel injectors. I was afraid it might be the head gasket because the misfires were on two adjacent cylinders and the coolant was a little low. Anyway, the mechanic told me head gasket failure is not unusual in 2010 and earlier models.
     
  8. jack black

    jack black Active Member

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    This is an excellent discussion. I do recall a discussion on BITOG way back trying to link an epidemic of Toyota water pump failures with then new pink ultra long life coolant (late 2000's) . There was no discussion on HG though. This reminds me to go ahead and replace coolants on my prius. I was going to wait for 10 years and closer to 120,000 miles for that to coincide with spark plugs, but I guess replacing plugs a bit early will not hurt. I do plan to do cylinder soaks to prevent oil consumption and EGR cooler cleaning to prevent HG problems at the same time.
     
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  9. Grit

    Grit Senior Member

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    Someone posted that engine coolant was to be changed at 100,000 mi.
     
  10. jack black

    jack black Active Member

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    I'm aware of that. I did a "partial" change at 70,000 when i cleaned TB and a lot of coolant spilled. Burping engine coolant in 2010 is painful BTW (improved in later years). Because there is limited space over the engine in Prius, I want to consolidate all that major maintenance into one long job (will do oil change after piston soak, too).
     
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  11. D’rae

    D’rae New Member

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    Hey all, found this thread via google looking as to why my 2012 Prius V is experiencing head gasket failure. OP, what did you end up doing and how does your Prius run now? I love my car—it’s on almost 140k miles but suddenly started shaking a lot on start up and idling. Took it to my local dealer to diagnose and got the crappy news
    Today. They said my head gasket failed and is leaking coolant into the engine and the repair will cost $3,700 (ouch!) told them to hold off u til I call my shop busy and see what they can do: they quoted me $1900 but warned that a head gasket repair on high mileage cars makes the engine more vulnerable or somethin. I’m not a car pro so I am wondering if a repair is worth it, invest in new engine, or trade up. Toyota needs to be aware that this may be a flaw in their manufacturing of cars for these years.
     
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  12. shin404

    shin404 New Member

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    My 2012 Prius Two with just 77,500 miles has a head gasket problem and is currently being fixed at my friend repair shop. (It would cost me $4,300.)

    if you have an issue with the head gasket, submit it on NHTSA website. They might investigate the issue and issue a recall.

    Shinji
     
  13. Grit

    Grit Senior Member

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    Join the lawsuit that a member here is putting together.
     
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  14. 2012 Prius v wagon 3

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    Wow, sorry to hear about that at such low mileage.

    I'm new to this, with a 2012 with about 55k miles, seems to be running fine. Thought I'd be WAY ahead of the game if I started with special preventive measures such as EGR cleaning, but maybe not. Are failures at such a low mileage as 77k extremely rare, or what? I'm sure somebody has compiled a histogram of HG failures vs. mileage; where is it? Thanks.
     
  15. Mendel Leisk

    Mendel Leisk Senior Member

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    55K is timely, maybe a little early, but debatable. I cleaned the EGR around 71K kms, plus Intake Manifold cleaning, plus Oil Catch Can install. The EGR was not badly clogged, but I don't regret doing it. I will probably repeat around 120K (kms).

    Not that I know of, but it seems like head gaskets fail a lot between 150K and 200K miles. Some sooner though. I think it's down to the the protracted overly-high combustion chamber temps, likely due to clogging EGR.
     
    #15 Mendel Leisk, Oct 12, 2019
    Last edited: Oct 12, 2019
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  16. Bill Norton

    Bill Norton Senior Member

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    But this is just your personal theory.
    There could be other reasons, right?
     
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  17. ColoPriusV

    ColoPriusV New Member

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    And my personal theory: the Gen 3 change to lighter weight 0-20W oil + extended 10K mile oil change intervals leads to oil breakdown, carbon deposits, more blowby gases and EGR carbon build up ... resulting in higher combustion temps and blown head gaskets. :(
     
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  18. Grit

    Grit Senior Member

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    Of course, Toyota won’t make car sales if we keep our Prius running as we drive pass their dealerships. Post planned obsolescence.
     
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  19. Grit

    Grit Senior Member

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    If ICE don’t get up to optimal temperature for long periods of time such as many short drives, you may experience it sooner than later. One person here had 44,000 mi and theirs began knocking.
     
    #19 Grit, Oct 16, 2019
    Last edited: Oct 17, 2019
  20. ColoPriusV

    ColoPriusV New Member

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    Not sure it's a conspiracy as much as a "failure to envision the future" ... but if Toyota doesn't step up and support their customers with a proper fix, then you're right - when gaskets blow a lot of us will be driving past the dealerships.
     
    #20 ColoPriusV, Oct 17, 2019
    Last edited: Oct 17, 2019
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