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

Pardon but I'm still confused about Prime coolant change.

Discussion in 'Prime Technical Discussion' started by The Big Sleaze, Dec 16, 2023.

  1. The Big Sleaze

    Joined:
    Nov 28, 2019
    286
    63
    0
    Location:
    'frisco
    Vehicle:
    2020 Prius
    Model:
    Two Eco
    tricks for coolant change on 2020 Primes? | PriusChat
    Got some info, but don't understand the desire for special equipment that "only takes about 20 minutes".

    Without special equipment from this Prime SPECIFIC youtube it seems fairly straightforward.

    1)You drain, removing air cap from engine side. Close drains.
    2)Refill, replace air cap, maybe squeeze engine side big hoses to get some more air out.
    On Refill, pay close attention to how much each side is Refilled, as that will tell you if you got air still in system and about how much.
    3)Run engine (I can't see any reason to put it in "Maintenance Mode") for a bit to top off coolants.
    4)Replace coolant tank caps, run engine some more, maybe short drive around block.
    5)Check levels (allow to cool before opening to top up).
    6)Drive some more, keep an eye on levels.

    Pretty much like any coolant change as far as I can see. In my other thread someone was talking about extended burping if you don't use the Special Equipment gizmo. Does that apply to PRIMES and besides checking and topping off coolant at most a couple times, how much burping is going on???

    No extended burping was mentioned in the Toyota manuals for 2016 (non-Prime) supplied by Mendel in my original thread.

    Is the only advantage of the Special Equipment method that you can be "all done and out the door" in 20 minutes so it might matter if you are a shop with a stack of other money making jobs to get to....
    but not so much for a DIY who has a couple other spare cars, so letting it cool and check a few hours later not really any issue???
     
  2. BiomedO1

    BiomedO1 Senior Member

    Joined:
    Mar 27, 2021
    1,474
    796
    0
    Location:
    SacTown, Ca
    Vehicle:
    2021 Prius Prime
    Model:
    LE
    The only thing I would get is a nylon hose that fits over the drain barb, to control the mess that would ensue when you open the drain.

    The only thing you missed is cranking up the heater to high and fan control to high, to help with the burping process.

    Re: the extended burping, it isn't needed. Most people mentioning this has a blown head gasket or exhaust gas heat exchanger leak - where exhaust gases are being pushed into their cooling system - so they go after the symptoms rather than the underlying problem. Following the OEM procedure should be enough; besides it only takes a few seconds to check coolant levels through the reservoir.
     
  3. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    55,564
    38,726
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Here's the repair manual instructions:




    Excuse the PITA format; it's the only way I figured out to upload files these days.
     
    PriusIzLife likes this.
  4. The Big Sleaze

    Joined:
    Nov 28, 2019
    286
    63
    0
    Location:
    'frisco
    Vehicle:
    2020 Prius
    Model:
    Two Eco
    thx again, I now see that is for 4th gen (17-22), just I guess first published in 2016.
     
    Mendel Leisk likes this.
  5. The Big Sleaze

    Joined:
    Nov 28, 2019
    286
    63
    0
    Location:
    'frisco
    Vehicle:
    2020 Prius
    Model:
    Two Eco
    I got only .75 quart out of inverter (3.5cups) and 3.5 quarts out of engine (14cups).
    I did remove both filler caps and the 6mm hex air vent from engine.
    What could I be doing wrong?

    Both those are about 1/2 the spec capacities.
    Oh, well, I guess I'll refill and count this as a "re-fresh" and figure out what is going on later.

    I do see a couple hoses and bottom or radiator that lies below the drains, but not enough to account for anything near 1/2 total volume.
     
  6. BiomedO1

    BiomedO1 Senior Member

    Joined:
    Mar 27, 2021
    1,474
    796
    0
    Location:
    SacTown, Ca
    Vehicle:
    2021 Prius Prime
    Model:
    LE
    Well, that seems to explain the 100K mile initial replacement and then 50K miles there after. We can't get all of it out, unless we do a flush. That would require full concentrated coolant, in order to get the dilution correct.

    I know you could rely on the dealership to do the task in the quickest and easiest way possible. ie. open the drain valves and call it a day..
     
    Mendel Leisk likes this.
  7. The Big Sleaze

    Joined:
    Nov 28, 2019
    286
    63
    0
    Location:
    'frisco
    Vehicle:
    2020 Prius
    Model:
    Two Eco
    Oh, thx. IIRC one YouTube the guy blows air, and IIRC he also says he used almost 2 gallons or pretty close to the spec capacity.
    I did hear some buzzing when I powered up to EV Mode and coolant in one (can't remember which) or both dropped a bit. What was that? Some pump in the inverter?

    I'd recommend doing coolant at more often than recommended on Toyotas. My metals experts tell me the alum alloy that is best for machining stuff like engine heads for mechanical wear and valve seating is also more prone to corrosion on the coolant side. My old Toyota truck finally gave up the ghost at about 380K due to porous aluminum head, and that just happened to be the one part you couldn't find even in rebuild-able condition for that model. I changed the oil but didn't think about coolant much.


    Genuine Toyota Parts - Genuine Toyota Fluid 00272-1LLAC-01 Long Life Coolant - 1 Gallon (002721LLAC01)
    probably do this next with distilled water flush.
     
    #7 The Big Sleaze, Dec 17, 2023
    Last edited: Dec 18, 2023