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Very scary noisy vibration on a cold start...occasionally

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by chuckiechan, Dec 15, 2020.

  1. chuckiechan

    chuckiechan Member

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    I had the ECM module replaced on recall/warrantee, and a week after it happened and my wife didn’t make it sound all that serious. She’s been driving as usual with no complaints and I forgot about it.
    This morning it happened to me. It scared the crap out of me and sounded like I thought I blew the engine! Imagine a out of balance engine with a bad motor mount kind of sound? We aren’t talking Tic, tic, tic here. It made noise. I immediately shut it off, re started, and it is fine. I’ve poked and wiggled in the engine compartment, but access is really poor.
    It only seems to happen in very cold conditions like for us 35-40 degrees.

    Obviously the dealer needs it to be repeatable, and I hope to catch it on video before a start.

    Does anyone has a similar experience?
     
  2. bisco

    bisco cookie crumbler

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    yes, many. it's just poor design by toyota.

    read through the egr threads, and check @NutzAboutBolts youtube channel.

    pray that you're ahead of a blown head gasket
     
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  3. rjparker

    rjparker Tu Humilde Sirviente

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    If it sounds like the beginning of this video, happens at initial cold start occasionally, it is likely the initial symptoms of a head gasket leak. Increasingly common on 2010-2015 Prius engines.

    The leak may be small and short enough not to dramatically drop the coolant level although coolant will be consumed. There are various tests to confirm.


     
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  4. chuckiechan

    chuckiechan Member

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    Wow. That’s it.
    Thanks. I guess I’m going to dealer trade in rather than sell it to a private party. Thanks so much!

    Why just when cold?
    BTW, I have like 75k miles so it may be time sensitive degradation.
    BTW, I had the ECM replaced recently and he told be I had “indications”, but if a trouble light came on it was covered by the emissions warranty. No trouble light in my case, so it would be on me.
    Arrrrgh!

    BTW, are the Prius 4’s any good?
     
  5. jdenenberg

    jdenenberg EE Professor

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    I had a 2016 Prius and there were no problems for 4 years and no problems for the 6 months on my new 2020 AWDe Prius.

    JeffD
     
  6. rjparker

    rjparker Tu Humilde Sirviente

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    The initial leaks are usually slow enough where it burns off without misfires once you are running well. After it cools off for hours the coolant has time to fill the cylinder and cause a misfire until it is pumped out of the cylinder. If you are unlucky enough to be at a low cylinder position full of coolant on the compression stroke, parts bend. Which is when things can get seriously beyond a headgasket repair.

    They fixed most of the issues by the fourth gen. Toyota even acknowledged and warranty repaired some piston ring problems if under the powertrain warranty.

    Were they saying they would fix a head gasket under the emissions warranty if codes occurred? Typical head gasket codes are usually misfires of the plugs.
     
    #6 rjparker, Dec 16, 2020
    Last edited: Dec 16, 2020
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  7. chuckiechan

    chuckiechan Member

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    Yes he did say that. Apparently a fouled or misfiring plug code causes the emissions trouble light, thus covered under warrantee. So far no code. I don’t know whether to be happy or sad.
    It sounds like a roll of the dice.

    BTW, do dealers report these things to Carfax, etc, dooming my trade in to a lowball offer?
     
  8. Grit

    Grit Senior Member

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    there are members in here that would scold you for pulling a move like that heh. Intentionally selling a vehicle that’s on its way out and an innocent buyer / dealership thinking they scored a good deal on it. Oh well, one man junk is another man’s treasure.
     
  9. Mendel Leisk

    Mendel Leisk Senior Member

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    Cautionary tale, 100k clean of EGR and intake manifold may be too late?
    Every 50k better?
     
  10. SFO

    SFO Senior Member

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    Check the most recent dealership entry by running the VIN at : Track Your Service Records with Your Toyota Owners Account

    Is the coolant level in the reservoir going down at all, the liquid level is around the plastic seam when cool or the hot line when hot.
     
  11. Mendel Leisk

    Mendel Leisk Senior Member

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    I don't recall 3rd gen has a "hot line". Top mark is just slightly above the horizontal seam, hard to see. Put a strip of masking tape on reservoir, mark coolant level with a Sharpie (say when cold), then monitor.

    Always recheck under same conditions, preferably level car and engine cold.
     
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  12. SFO

    SFO Senior Member

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    Looks like the hot line is labeled ' B ' for boiling?

    Example here :

    [​IMG]
     
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  13. Mendel Leisk

    Mendel Leisk Senior Member

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    I'll have to check. It's the top line and says "FULL" anyway.
     
  14. chuckiechan

    chuckiechan Member

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    It doesn’t seem to be loosing coolant. Nov 2 was the dealer ECM install, and the fluid is still there. It must be minuscule.
     
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  15. bisco

    bisco cookie crumbler

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    or non existant. i wouldn't rush to get rid of it.
     
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  16. Siward

    Siward Active Member

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    I have exactly the same problem. Once in a long while my Prius shakes/rumbles on startup. I find it more likely happens when:
    1) Startup in colder weather
    2) Startup after driving the car for short distances and leaving it off for more than a day.
    3) Startup problems are less likely after driving car for long trips so that the engine gets hot.

    It seems to be the #1 problem on PriusChat for the gen 3 Prius. There are range of possibilities including:
    1) Clogged EGR or pipe
    2) Clogged intake manifold
    3) Starting signs of headgasket failure

    Since the startup problems don't happen often, I have simply done nothing about it. There will be a day I will have to do something about it. Toyota is known for reliability, but this is a disappointment.

    Prior to COVID-19, I used to commute to work and drove the car 1-2 hours a day. The startup shaking never happened on a work day. It also never happens if you restart the car immediately after a long drive. I would say the car is not designed to be driven less.
     
    #16 Siward, Dec 17, 2020
    Last edited: Dec 17, 2020
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  17. rjparker

    rjparker Tu Humilde Sirviente

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    Watch the coolant level. A normal engine won't lose a drop. Head gasket failures on these cars start small and act just as you describe. Until the day it quits and the hybrid failure light comes up. Even then it may run but with the shaking happening more often and eventually with white steam coming out of the exhaust. Then its either death by overheating or a rod breaks. It is disappointing and even more so when fanboys here downplay it because their car is fine. It is especially sad when someone has just paid good money for a 2010-14 only to see symptoms shortly after the seller's can of block sealer has worn off.
     
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  18. chuckiechan

    chuckiechan Member

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    I did that. It only talked about the warranted repair. The “VIM”.
     
  19. chuckiechan

    chuckiechan Member

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    I have decided to run it until it breaks, or at least inform the next buyer. I could not in clear conscience stick some poor person with a big bill. The shaking is a rare event, but I can afford to fix it if it goes. Hybrid failure is covered inder warranty.
    I’m wondering if I ran 100% antifreeze as coolant? I think at even high normal operating temperatures, there would be little or no pressure in the system, solving the problem of coolant pressure forcing coolant into the combustion chamber. We dont get very cold here, plus the car is garaged. But it gets very hot.
    Back in the day I ran 100% coolant in my Ford Courier with no problems.

    How far off the mark am I?
     
    #19 chuckiechan, Dec 27, 2020
    Last edited: Dec 27, 2020
  20. Mendel Leisk

    Mendel Leisk Senior Member

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    100% is LESS able to do its cooling job If I recall correctly. Not recommended.

    You’re concentrating on symptoms, not the cause. My 2 cents: I’d rather deal with failing head gasket and clean the EGR/intake, than a hydrolocked door stop. But it’s your nickel, lol.