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

How to flush or access heater core?

Discussion in 'Gen 2 Prius Main Forum' started by oil_burner, Feb 8, 2019.

  1. oil_burner

    oil_burner Active Member

    Joined:
    Feb 26, 2017
    249
    126
    0
    Location:
    Canada
    Vehicle:
    2006 Prius
    Originally I had a problem with a leaking head gasket that has now turned into a much bigger problem because I elected to try a bottle of bars head gasket sealant. It did not fix the leak and now I have partially blocked the heater core. The cabin heat is only blowing hot out of 3/4 upper vents and taking a long time to reach temperature.

    I am installing a new engine in next week, any ideas on how best to flush out the entire coolant system? I don't want further problems down the line so I am open to disassembling the dash to remove the heater core completely, hook it up to a pressure washer to blow it out. I am just not sure of how to get access to it.

    As well I plan to clean out all the T's in the system the only 3 I can think of are the one at the coolant recovery bottle/pump, the 3 way valve next to the radiator, and the thermostat. Does that cover all of them? Basically I will be taking every hose apart and running a cleaning brush/flushing. And let this serve as a lesson to all of you thinking that head gasket in a bottle repair is ever a good idea... :cry:
     
    #1 oil_burner, Feb 8, 2019
    Mendel Leisk likes this.
  2. audiodave

    audiodave Active Member

    Joined:
    Feb 3, 2017
    783
    268
    0
    Location:
    US
    Vehicle:
    2004 Prius
    Model:
    Five
    #2 audiodave, Feb 8, 2019
  3. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,662
    38,207
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Is that stuff PeptoBismol bright pink? I've watched a third gen head gasket repair video; the coolant passages had that appearance.
     
    #3 Mendel Leisk, Feb 8, 2019
  4. oil_burner

    oil_burner Active Member

    Joined:
    Feb 26, 2017
    249
    126
    0
    Location:
    Canada
    Vehicle:
    2006 Prius
    its a red color with a lot of floating bits in it, it didn't block the heater core until about a month later.
     
    #4 oil_burner, Feb 9, 2019
    Mendel Leisk likes this.
  5. audiodave

    audiodave Active Member

    Joined:
    Feb 3, 2017
    783
    268
    0
    Location:
    US
    Vehicle:
    2004 Prius
    Model:
    Five
    #5 audiodave, Feb 9, 2019
  6. audiodave

    audiodave Active Member

    Joined:
    Feb 3, 2017
    783
    268
    0
    Location:
    US
    Vehicle:
    2004 Prius
    Model:
    Five
    #6 audiodave, Feb 9, 2019
    Skibob likes this.
  7. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,662
    38,207
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Found this, maybe worth a try, Thoro-Flush:



    Amazon link, may need to turn off your adblock:



    They recommend to run with this stuff for only 15 minutes, then flush. One possible issue: you want this stuff flowing through the cabin heater core as much as possible, and that can be delayed until temp is is high enough. Maybe when mixing the product use hottest available tap water?
     
    #7 Mendel Leisk, Feb 9, 2019
    Last edited: Feb 9, 2019
    oil_burner likes this.
  8. oil_burner

    oil_burner Active Member

    Joined:
    Feb 26, 2017
    249
    126
    0
    Location:
    Canada
    Vehicle:
    2006 Prius
    I worry about using something very strong like that, if I'm not able to flush it completely out it could lead to another head gasket failure down the road or ruin my water pump. Acidic coolant is the number one cause of head gasket failure, so I'm told. I think I'll try to find the inlet of the heater core and attach a pressure washer to it.
     
    #8 oil_burner, Feb 10, 2019
    Mendel Leisk likes this.
  9. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,662
    38,207
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Maybe use motorized suction instead of pressure; I just had a dreadful thought: about what might happen if something blew or came loose under the dash.

    A shop vac capable of wet operation with reversible hoses to the suction side would be good.
     
    #9 Mendel Leisk, Feb 10, 2019
    Last edited: Feb 10, 2019
    anonymous likes this.
  10. Skibob

    Skibob Senior Member

    Joined:
    Sep 14, 2018
    2,912
    1,496
    0
    Location:
    Northern California
    Vehicle:
    2006 Prius
    Model:
    N/A
    High pressure will just blow the heater core out. You can try reverse flushing but I would stick to lower pressures, like what comes out of the hose and plenty of it. It’s probably clogging your radiator also so your going to need to clean that. Plus the thermos and electric water pumps. Someone was asking about that type of sealer lately, I remember saying to never use it. Shit always causes more problems than it fixes. Guess you can vouch for that. :(
     
    #10 Skibob, Feb 11, 2019
(You must log in or sign up to post here.)