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

sudden coolant consumption, options to prevent HG failure?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by jack black, Nov 23, 2020.

  1. rjparker

    rjparker Tu Humilde Sirviente

    Joined:
    Jun 6, 2008
    7,471
    4,373
    7
    Location:
    Texas Hill Country
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    Damn, I can't respond.
     
    #41 rjparker, Dec 29, 2020
    Last edited: Dec 29, 2020
    Grit likes this.
  2. Grit

    Grit Senior Member

    Joined:
    Aug 22, 2017
    6,103
    4,032
    1
    Location:
    Wilkes Land
    Vehicle:
    2012 Prius
    Model:
    Four
    :cool::cool::cool::cool::cool::cool::cool::cool::cool::cool::cool::cool::cool::cool::cool:
     
  3. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,467
    38,101
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    You made me go back a page and disable my ignore list. :LOL:
     
    Grit likes this.
  4. Grit

    Grit Senior Member

    Joined:
    Aug 22, 2017
    6,103
    4,032
    1
    Location:
    Wilkes Land
    Vehicle:
    2012 Prius
    Model:
    Four
    :ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO:
     
  5. jzchen

    jzchen Newbie!

    Joined:
    Apr 9, 2012
    3,295
    1,005
    0
    Location:
    Arcadia, CA
    Vehicle:
    2012 Prius v wagon
    Model:
    Five
    And no knocking since? I think that's the winning attribute...

    moto g(7) power ?
     
  6. jack black

    jack black Active Member

    Joined:
    Jan 5, 2018
    225
    142
    0
    Location:
    USA
    Vehicle:
    2010 Prius
    Model:
    I
    correct. except for once my wifey started the ICE for seconds as she was repositioning the car in the driveway. it briefly knocked on the next start as expected. i make sure i use the car daily, and it goes through full warm up cycles now.

    thanks for asking.
     
    jzchen likes this.
  7. Rocky Mountain Priusman

    Rocky Mountain Priusman Active Member

    Joined:
    Mar 15, 2021
    212
    109
    0
    Location:
    Canmore, Alberta, Canada
    Vehicle:
    2010 Prius
    Model:
    Four
    Can you give us an update #3 now that its been a few more months?
     
    jack black and Bohemian Grove like this.
  8. jack black

    jack black Active Member

    Joined:
    Jan 5, 2018
    225
    142
    0
    Location:
    USA
    Vehicle:
    2010 Prius
    Model:
    I
    No problem. Sorry for the delay. Life [outside forums] happens.

    The update #3: the coolant consumption is negligible since. I refilled a couple of hundreds cc after lots of hwy and mountain driving with heavy use of engine braking. I monitored the coolant temps in a few city and hwy trips. the city averaged 85C, while the hwy averaged 95C. I changed oil a couple of months ago, 10,000 miles, more than half while having the coolant issue, and the used oil analysis was negative for glycol or water. The oil always looked good with no evidence of emulsion whatsoever. The wear elements were lower than i expected. I'm positive the coolant is not going into oil in my car. I'm clueless where it's going. I don't see anything dripping.

    Here is my next hypothesis. Maybe some early gen 3 prius engines develop obscure external head gasket leaks or other weird ways of slow coolant consumption after 100,000 miles (could it be going into exhaust?). If one doesn't check the coolant levels, is not proactive correcting the problem, or simply doesn't replace the lost liquid, the engine overheats and warps the head and ruins the HG in a catastrophic way.

    Feel free to discuss (with no intimidation or bullying).
     
  9. Grit

    Grit Senior Member

    Joined:
    Aug 22, 2017
    6,103
    4,032
    1
    Location:
    Wilkes Land
    Vehicle:
    2012 Prius
    Model:
    Four
    :LOL:
     
  10. rjparker

    rjparker Tu Humilde Sirviente

    Joined:
    Jun 6, 2008
    7,471
    4,373
    7
    Location:
    Texas Hill Country
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    I call it self sealing head gasket leaking coolant into a cylinder. It can be very occasional at first and is the typical Prius 1.8 hg failure mode. Just enough coolant to foul the plug for a few seconds, lose MG sync and rattle the clutch damper. Then it seals up and runs fine. It absolutely goes out the exhaust but its so little at first you don't see white smoke. Often leaves a cleaner piston top. Typically no coolant leaks into the oil. Its more than a hypothesis, its what happens as documented by local dealer mechanics.
     
    #50 rjparker, Jul 17, 2021
    Last edited: Jul 17, 2021
    Samuel Williams Jr and cnc97 like this.
  11. jzchen

    jzchen Newbie!

    Joined:
    Apr 9, 2012
    3,295
    1,005
    0
    Location:
    Arcadia, CA
    Vehicle:
    2012 Prius v wagon
    Model:
    Five
    The car I used the K-Seal on, is still leaking coolant. I've narrowed it down to the reservoir cap. I guess because of it's thickening nature there is higher than normal pressure and it is being relieved through the pressure release in the cap, 2013 Panamera GTS (NA V8) just as an FYI. The formulation is ceramic based, so I used to smell it (kind of like taking pottery class with the wet clay), around the engine bay and in the cabin from I'd guess a small heater core leak that were eventually sealed. You can buy a relatively cheap pressure tester/vacuum filler kit on eBay and test for coolant leak. I find no evidence of leaking using such a device, hence the cap and possibly heater core theory. If you haven't recently try replacing the cap. At least per K-Seal instructions, the repair is supposed to be permanent, (hence why I recommend it). But I have not tested that by replacing the coolant with fresh fluid. The GM equivalent tabs were made to be used at each coolant replacement so I'd guess the same for the BARs that you used.

    This store is near enough I go there to buy in person. This is the type of kit I'm talking about. Haven't tried it on the Prius ours only has 32k mi roughly so not much wrong.

    28PC MASTER RADIATOR PRESSURE TESTER KIT COOLANT VACUUM PURGE REFILL W/ADAPTERS – EconoSuperStore

    moto g(7) power ?
     
    #51 jzchen, Jul 18, 2021
    Last edited: Jul 18, 2021
  12. tony_2018

    tony_2018 Member

    Joined:
    Jun 12, 2019
    204
    58
    0
    Location:
    78717
    Vehicle:
    2012 Prius
    Model:
    IV
    Can you provide a screenshot or pic of the oil analysis?
     
    jack black likes this.
  13. jack black

    jack black Active Member

    Joined:
    Jan 5, 2018
    225
    142
    0
    Location:
    USA
    Vehicle:
    2010 Prius
    Model:
    I
    The final update is here! I found the source of the coolant leak. I did inspection of the engine compartment (again) and found some signs of dried coolant on the top of the tranny. There are places the coolant pools in and dries. This is why there was never a dripping coolant. Above it is the coolant burping valve that i used over 2 years ago when i did the coolant service. it was tight, but i tightened it up. It wasn't it, still signs of wet coolant on the top of tranny. I looked around where else the coolant could be coming from and then i noticed a line of dried coolant on the side of EGR cooler. I looked closer and (the horror!) the clamp over coolant line on the top of the cooler was not positioned properly, it was too high. I must have missed it when i did the ERG service. Why it only started leaking recently is only my guess. This explains why the coolant leak pellets worked to some extend. I'm so glad I did the UOA and I didn't do any silicate coolant treatments. Now, I need to replace the coolant again, probably with preventive water pump service and intake cleaning, too.
    Thank You All who supported me here (as opposed to trolling and ridiculing)!
    I'll post the UOA report later after doing some yard work.
     
    #53 jack black, Jul 24, 2021
    Last edited: Jul 24, 2021
    ASRDogman likes this.
  14. ASRDogman

    ASRDogman Senior Member

    Joined:
    May 29, 2018
    5,834
    3,136
    0
    Location:
    Florida
    Vehicle:
    2010 Prius
    Model:
    Two
    Dd you do a pressure test? Or just found it?
    You NEVER want to put ANYTHING in the coolant system except the correct coolant!
    You'll clog the radiator, heater core, engine block passages... etc.....

    Glad you found it! Everyone misses things sometimes, no one is perfect!
    Hopefully, this resolves your coolant leak!

     
  15. jack black

    jack black Active Member

    Joined:
    Jan 5, 2018
    225
    142
    0
    Location:
    USA
    Vehicle:
    2010 Prius
    Model:
    I
    no problem. uploaded. my name and address removed.

    Untitled.jpg
     
  16. tony_2018

    tony_2018 Member

    Joined:
    Jun 12, 2019
    204
    58
    0
    Location:
    78717
    Vehicle:
    2012 Prius
    Model:
    IV
    Depending on the miles I'd say it's time to replace those smaller coolant hoses. All of them, pricey but peace of mind. Yeah add the inverter coolant pump too. I kid you not. Get. It. Done.