No Heat

Discussion in 'Gen 2 Prius Main Forum' started by qmanqman, Oct 20, 2025 at 12:58 PM.

Page 2 of 2
  1. qmanqman

    qmanqman Active Member

    Joined:
    Mar 29, 2020
    413
    136
    0
    Location:
    CO
    Vehicle:
    2007 Prius
    Model:
    One
    Ya I checked it this morning and had to add a few oz's. I'll keep checking after every drive.
     
    #21 qmanqman, Oct 22, 2025 at 11:36 AM
    BiomedO1 likes this.
  2. pasadena_commut

    pasadena_commut Senior Member

    Joined:
    May 2, 2019
    2,518
    752
    0
    Location:
    Southern California
    Vehicle:
    2007 Prius
    Model:
    N/A
    That's a lot. I would suspect a leak. Have the radiator cap tested. One way they fail is that they open up at too low a pressure, but high enough that the coolant just evaporates when it blows out. Result: mysteriously disappearing coolant.
     
    #22 pasadena_commut, Oct 22, 2025 at 1:50 PM
  3. qmanqman

    qmanqman Active Member

    Joined:
    Mar 29, 2020
    413
    136
    0
    Location:
    CO
    Vehicle:
    2007 Prius
    Model:
    One
    Ya I'll figure it out. Usually a leak presents itself with the smell of coolant. I have never smelled coolant which would mean that it is either so small you won't smell it or the leak is internal. Either way I'm on it.
     
    #23 qmanqman, Oct 23, 2025 at 2:36 PM
    BiomedO1 likes this.
  4. pasadena_commut

    pasadena_commut Senior Member

    Joined:
    May 2, 2019
    2,518
    752
    0
    Location:
    Southern California
    Vehicle:
    2007 Prius
    Model:
    N/A
    Our Accord had the "bad radiator cap" leak. There was no clue, coolant just disappeared with no sign of it anywhere. We looked everywhere, even inside the cylinders with the radiator pressurized, in case there was a head gasket problem. Didn't make any sense until the cap was tested and found to be defective. (Ordered a replacement from RockAuto, not OEM but a well known and usually reliable brand. Luckily still had the rental radiator tester when it came. The replacement cap wouldn't open, even at pressures far above its rating. Gave up and bought an OEM cap for several multiples of the nonOEM's cost at the closest dealer's parts department and all was good.)
     
    #24 pasadena_commut, Oct 23, 2025 at 6:42 PM
(You must log in or sign up to post here.)
Page 2 of 2