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

Is it really an internal coolant leak?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by AW0311, Sep 16, 2017.

  1. AW0311

    AW0311 New Member

    Joined:
    Feb 26, 2017
    2
    0
    0
    Location:
    Rocklin, CA
    Vehicle:
    2007 Prius
    Model:
    I
    Hi Prius Community,

    My 07 Prius recently hit 400,000 miles and I just experienced the red triangle of death along with the temperature light and problem warning signals. I took my car into the dealership and after a diagnostic test was told that I had a faulty radiator cap. I bought the $230 radiator cap (which included the diagnostic) and the car ran fine again for another 150 miles. The warning light and temperature light came back on so I turned my heater on to see if I could smell any burning oil. I didn't smell any burning oil but I did notice the heater would blow cold air and then hot air intermittently (The AC works just fine and the warning lights also went away). I took the car back to the dealership and was told I have an internal coolant leak. I've checked my oil dipstick and cap and don't see the frothy milk signs of a coolant leak. I don't have a decrease in coolant or an increase in oil. Other than the warning lights my car seems to be running fine. I had my oil changed at the dealership a week prior to experiencing this problem and wasn't told that I had any problems with fluid levels. Considering that my diagnosis went from faulty radiator cap to internal coolant leak I'm wondering if the mechanics are just throwing darts at a Toyota manual to diagnose my problem. Anyone out there have any similar experience with this issue?
     
    #1 AW0311, Sep 16, 2017
  2. jadziasman

    jadziasman Prius owner emeritus

    Joined:
    Jan 17, 2011
    1,355
    487
    0
    Location:
    District 6
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    What were the error codes that the stealership read and apparently cleared? We will need them to help you.

    Did the dealer do a cooling system pressure test? They should have if they thought the radiator cap was bad.
     
    #2 jadziasman, Sep 16, 2017
    Last edited: Sep 16, 2017
  3. Raytheeagle

    Raytheeagle Senior Member

    Joined:
    Jul 1, 2016
    11,251
    15,477
    0
    Location:
    Bay Area, California
    Vehicle:
    2019 Prius Prime
    Model:
    Prime Plus
    Welcome to Prius Chat (y)!

    Which one of the many Sacramento area dealers are you using? Did they give you a print out of the codes?

    400 k miles is impressive :).

    Keep us posted(y).
     
    #3 Raytheeagle, Sep 16, 2017
    Last edited: Sep 16, 2017
  4. JC91006

    JC91006 Senior Member

    Joined:
    Nov 10, 2013
    16,470
    8,384
    0
    Location:
    Los Angeles, CA
    Vehicle:
    2008 Prius
    Model:
    II
    I think they're throwing darts.

    Have you tried bleeding air out of the coolant loop? Is the radiator full?

    If there's a leak, it would most likely come from the water pump. However if you've driven the car while it's overheating, it could cause a head gasket issue.
     
    #4 JC91006, Sep 16, 2017
  5. AW0311

    AW0311 New Member

    Joined:
    Feb 26, 2017
    2
    0
    0
    Location:
    Rocklin, CA
    Vehicle:
    2007 Prius
    Model:
    I
    I took my car to Roseville Toyota and the notes from the first visit were: "Suspect cap failed and pushed coolant out of radiator and would not recover from overflow. Road tested several miles with Tech Stream, coolant temperature stays approximately 190, normal. Radiator cap inspected, connected Tech Stream, no codes present, found coolant reservoir full, radiator is low, added coolant to radiator, adjusted overflow level, inspected for leaks, only dried residue from overflow.

    These were the notes after my second visit: "Removed coils and plugs, pressurized cooling system and inspected cylinders with borescope. Found #1 cylinder has coolant leaking into combustion chamber. Head gasket has failed and will need to be replaced to correct concern". The notes from the second visit sound pretty ominous, but considering there were no error codes from the diagnostic and the diagnosis went from radiator cap to head gasket overnight it makes me wonder whether an inspection with a borescope was ever conducted.

    To make matters worse, now that I'm more in tune to the problem, I'm starting to hear a sloshing of water from the engine compartment when I'm driving. I've had the water pump replaced several months ago at the dealership so I'm not sure how any of this might be related.
     

    Attached Files:

    #5 AW0311, Sep 16, 2017
  6. jadziasman

    jadziasman Prius owner emeritus

    Joined:
    Jan 17, 2011
    1,355
    487
    0
    Location:
    District 6
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    With 400K miles, you've had a good run. If you can install a used engine with low miles cheaply you could extend its life a few more years. However, this might be the right time to put her down.
     
    #6 jadziasman, Sep 16, 2017
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,200
    6,464
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    There are no error codes associated with a failed head gasket.

    The sloshing of coolant probably is due to air that has entered the engine coolant system, since the radiator level was low.

    Get rid of the car, install a used engine, or else replace the cylinder head gasket (I would not recommend doing the gasket, since the engine would certainly be worn out after 400K miles.)
     
    #7 Patrick Wong, Sep 16, 2017
    Samuel Williams Jr likes this.
  8. 05PreeUs

    05PreeUs Senior Member

    Joined:
    Oct 1, 2016
    1,097
    563
    0
    Location:
    MSP
    Vehicle:
    2005 Prius
    Model:
    N/A
    I apologize in advance for the multi-quote, but.... it is necessary in this case :(

    I am calling BS on that!!!!! If you had a triangle and light, THERE ARE CODES, period.

    That's just stupid, throwing darts as someone else posted hoping to cash in and it cost YOU.

    Agreed, especially since you KNEW to look at the oil and found no evidence of moisture. With a leak like they CLAIM, you WILL have coolant in the oil. However, it does explain disappearing coolant and repeatedly getting air in the heater circuit.

    It would seem that:
    a) They may not have completely purged air from the cooling system after the water pump was replaced
    b) Coolant level was low exposing the engine to a potential overheat
    c) Overheating will kill a head gasket, immediately.
    d) They owe you for the cost of RO#1 diagnostics and the cap, as it was a BS "repair"
    e) I do not believe the HG was failed when you brought the car in, or you would have seen moisture in the oil (increasing level or gelly-like appearance)

    It is important to note that many modern anti-freeze/coolant mixes DO NOT create the yellowish milky froth we are accustomed to seeing in oil when there is a contamination issue. More often modern coolants change the consistency of the oil and do not present with the "froth".
     
    #8 05PreeUs, Sep 17, 2017
    Samuel Williams Jr likes this.
  9. 400kclub

    400kclub New Member

    Joined:
    Jun 11, 2021
    18
    4
    7
    Location:
    SC
    Vehicle:
    2009 Prius
    Model:
    Base
    In case anyone else happens upon this post, I too have a Prius with 406k miles with this exact issue except I’m getting a small number of cylinder 1 misfires which were occurring sometimes when the engine cycled on.

    Scotty Kilmer (great vids on YouTube btw!) recommended sodium silicate in your coolant system which can be used on head gasket leaks as it hardens to a rock past 120 degrees Celsius.
    I added Bar’s Block Seal Liquid Copper (contains sodium silicate) to the radiator 2 days ago and haven’t had a misfire since. Scotty mentioned an instance where he used sodium silicate in a Honda and the car was still running a couple years later. It’s pretty sticky stuff so if I were to do
    it again, I would probably recommend using 1/4 of the bottle instead of the 1/2 recommended in the instructions. You’re supposed to run the engine with the heat on high for 15 minutes after adding to the radiator. To do so, look up how to put the Prius in “inspection mode”.

    I will provide updates on how this works.
     
    #9 400kclub, Jul 3, 2021
(You must log in or sign up to post here.)