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

  1. PixelRogue

    Joined:
    Apr 5, 2010
    315
    57
    0
    Location:
    US
    Vehicle:
    2012 Prius Plug-in
    Model:
    N/A
    Today some smoke (vapor) started exiting a temperature vent above the radio. Various testing would state the smoke was only present when the outside vent mode was on, and most times after acceleration.

    Pulled over, popped the hood and noticed low coolant in the reservoir closest to left of engine (while facing engine from outside, in front of passenger seat). Swung by a Toyota dealership, picked up some replacement coolant, topped it off and car is back to normal. Simple, easy stuff.

    In some of the googling and videos and such, noticed references to flushing the coolant, as it needs to be replaced about every 100,000 miles or so. Other than a guess in terms of 'for good measure' or 'its about time' preventative maintenance, how would one 'know' (for certain) the coolant fluid would be bad, in need of replacement?

    I am handy enough to drain and refill...albeit getting under the car will be a pia.
     
  2. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,463
    38,101
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Watch the level on the reservoir for a week or two. If it continues to drop, could be failing coolant hose, radiator damage. Or head gasket failing.

    How many miles on it?
     
  3. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,463
    38,101
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    First engine coolant change is slated for 100K miles or 10 years. First inverter coolant change is 150K miles or 15 years. Thereafter, both are 50K miles or 5 years.
     
    Greenteapri likes this.
  4. PixelRogue

    Joined:
    Apr 5, 2010
    315
    57
    0
    Location:
    US
    Vehicle:
    2012 Prius Plug-in
    Model:
    N/A
    120k
     
    Mendel Leisk likes this.
  5. PixelRogue

    Joined:
    Apr 5, 2010
    315
    57
    0
    Location:
    US
    Vehicle:
    2012 Prius Plug-in
    Model:
    N/A
    I was thinking of doing them together at the same time, given everything is already there and open...might as well do both?

    I will keep an eye on the levels.

    How do you know when the coolant itself has gone bad though? So there are estimated time frames for a change...curious how you know when it has spoiled.
     
  6. Rebound

    Rebound Senior Member

    Joined:
    Mar 11, 2010
    3,961
    2,609
    0
    Location:
    Portland, OR
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    Coolant doesn’t just vent out of your car unless there’s a leak or a serious overheat event. If there’s no leak when the engine is hot, maybe the leak is in the heater core, which means it will leak when the heater is on.

    If it seems ok... proceed with care until you’re sure the problem doesn’t return. Monitor the coolant level at least daily.

    As for a coolant flush, I think you should wait two weeks, to be sure you don’t have a leak.
     
    RMB, The Critic, jerrymildred and 2 others like this.
  7. TMR-JWAP

    TMR-JWAP Senior Member

    Joined:
    Aug 12, 2016
    6,058
    5,783
    0
    Location:
    Columbia, SC
    Vehicle:
    2007 Prius
    Model:
    Touring
    PixelRogue and Rebound like this.
  8. jb in NE

    jb in NE Senior Member

    Joined:
    Apr 13, 2018
    2,233
    1,595
    0
    Location:
    Nebraska
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Premium
    If you are getting vapor from the interior vents, this may point to a leak in the heater core. If this is the case, you wil also get a slimy/sticky buildup on your interior glass from the glycol.
     
    mjoo likes this.
  9. Rebound

    Rebound Senior Member

    Joined:
    Mar 11, 2010
    3,961
    2,609
    0
    Location:
    Portland, OR
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    That’s what I was thinking... which explains why the problem went away... it’s summertime and hot out. He isn’t using the heater.
     
  10. AzWxGuy

    AzWxGuy Weather Guy

    Joined:
    May 22, 2011
    959
    485
    0
    Location:
    Tucson, AZ
    Vehicle:
    2021 Prius
    Model:
    Limited
    If it is a heater core leak (sounds likely), wouldn't the heater loop continue to be pressurized similarly to the ICE cooling loop and therefore continue to leak? Unless of course there are two valves controlling the heater loop flow, which I doubt but don't know for sure. The only other time I've seen vent vapor such as this was under high humidity air intake from outside, which the OP does state sans any statement about humidity (location is US which could be anywhere), and initial air conditioner operation. After a while the interior air is cooled and de-humidified enough to eliminate vapor condensation from the vent.
     
    CR94, mjoo and jb in NE like this.
  11. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,463
    38,101
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    #11 Mendel Leisk, May 31, 2019
    Last edited: May 31, 2019
  12. PixelRogue

    Joined:
    Apr 5, 2010
    315
    57
    0
    Location:
    US
    Vehicle:
    2012 Prius Plug-in
    Model:
    N/A
    So let's say there is a heater core leak,
    Yesterday was the first notice of any vapor through a vent; have not noticed any signs of issues (no build ups on window during cold weather. Discovered a rather low coolant reserve when popping the hood. Added OEM SLL coolant and everything was normal afterwards.

    Currently monitoring levels to determine if there are any leaks.
     
  13. Rebound

    Rebound Senior Member

    Joined:
    Mar 11, 2010
    3,961
    2,609
    0
    Location:
    Portland, OR
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    Did you turn on the heater?
     
  14. 2014

    2014 Member

    Joined:
    May 8, 2019
    30
    31
    0
    Location:
    MA
    Vehicle:
    2014 Prius
    Model:
    Four
    Did you have the AC on? Was the humidity high? Could have been cold AC air causing warm humid air to condense into visible vapor. Low coolant level may be a coincidence and have nothing to do with it.
     
    jb in NE likes this.
  15. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,463
    38,101
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Ok, this is completely off the wall, but am I the only one thinking your user name is MARTINI, and you joined in 2014.

    Good coffee...
     
    Grit likes this.
  16. Grit

    Grit Senior Member

    Joined:
    Aug 22, 2017
    6,103
    4,032
    1
    Location:
    Wilkes Land
    Vehicle:
    2012 Prius
    Model:
    Four
    Those are my moments here also but with dark red wine.
     
    RMB, Greenteapri and Mendel Leisk like this.
  17. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,463
    38,101
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Or a martini.
     
  18. PixelRogue

    Joined:
    Apr 5, 2010
    315
    57
    0
    Location:
    US
    Vehicle:
    2012 Prius Plug-in
    Model:
    N/A
    Remaining hopeful that that the low coolant would be a coincidence.
    At the same time, winds are pointing to a coolant leak. I topped off the coolant on Thursday (and would wait for the liquid to settle at the high level mark in the coolant reservoir (located left of engine, in front of passenger seat.))

    Had some long drives since Thursday... placed about 400 miles, 1/2 would be highway. Today, I notice the coolant level at the 'low' level mark. Only disparity I can think of would be a warm engine when coolant was added, cool engine this morning.

    So, I am monitoring for a coolant leak.
     
    Mendel Leisk likes this.
  19. PixelRogue

    Joined:
    Apr 5, 2010
    315
    57
    0
    Location:
    US
    Vehicle:
    2012 Prius Plug-in
    Model:
    N/A
    Thinking ahead (while hoping there is no leak) ~ how would you actually identify the source of the leak itself? I have not yet seen any liquid on the ground to even know what quadrant of the engine to start looking. A few tutorials are about replacing

    Possibilities:
    - coolant flow control valve
    - water pump
    - heater control
    - thermostat
    - cracked hose

    Stating the obvious, yet putting in writing helps think through the issue.
     
  20. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,463
    38,101
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Add head gasket failure to that list. Check through the spark plug holes with a boroscope, and/or leak-down test.