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

Coolant Hi Temp warning

Discussion in 'Gen 2 Prius Main Forum' started by Harrywalpole, Jun 4, 2018.

  1. Harrywalpole

    Harrywalpole Junior Member

    Joined:
    Oct 8, 2014
    5
    0
    0
    Location:
    02071
    Vehicle:
    2008 Prius
    Model:
    N/A
    08. With 182K miles, coolant high temp warning flashes intermittently after 10 mins of driving over 50 mph. If I put heater on it blows cold air. Had to add 1/2 gal to radiator directly , other reservoirs ok. Problem not as frequent the cooler the ambient air, but still there
     
  2. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    108,947
    49,512
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    leak? thermostat? air in the system? water pump?
     
    Raytheeagle likes this.
  3. JC91006

    JC91006 Senior Member

    Joined:
    Nov 10, 2013
    16,482
    8,400
    0
    Location:
    Los Angeles, CA
    Vehicle:
    2008 Prius
    Model:
    II
    You might have a leaking water pump, confirm it's condition and condition of the belt it's attached to, change if needed.

    For now top off the coolant in the radiator every morning until you see it full and doesn't require topping up.

    It's also a good idea to change the radiator cap too
     
    Raytheeagle likes this.
  4. 09Prius2

    09Prius2 Member

    Joined:
    Aug 20, 2016
    201
    88
    0
    Location:
    FL
    Vehicle:
    2009 Prius
    Model:
    Two
    Yeah. Start with cap and pump.

    I just went through the same with my 08. 2 Toyota dealers, first says nothing wrong and 2nd replaced new radiator cap again for $137.

    Blown head gasket.

    Put a funnel in the radiator neck and leave the car on with the ac on.

    The bubbles that come out of the funnel will tell you everything. When bubbles come out, sniff them for exhaust.

    If you smell exhaust fumes bubbling out with the radiator cap off, you'll know it's curtains for your prius.