I heard about some lengthy process, but this seems fairly straight forward. 1)Open engine and inverter coolant filler caps. 2)Drop the under panels to get to 2 yellow drains on driver's side. 3)Drain both coolants. 4)Close drain valves. (now this guy IIRC replaces the under panels THEN fills and runs to 'burp'. I'm gonna fill, run to burp, check for leaks, let it cool back down, THEN do the under panels) 5)Replace panels. 6)Run to burp system and refill as level of Inverter drops. 7)Replace filler caps. This guy does some fancy thing to put it in "maintenance mode" but vid is older and not of a Prime. I think I'll just start with fairly low traction battery so it can be in CRG mode for a while. Questions are: What is coolant capacity for both engine and inverter? How much do I need to buy? In second video the guy says its important to eyeball that the coolant in inverter is showing motion, so its not cut off by some big air bubble. He also lets it start engine cooling fans twice as per specs. Does the coolant ever want to boil up and out like with old cars? Video was shot out of sequence so do you replace caps with engine still running?
Attached are Toyota Repair Manual instructions. Doesn’t matter Prime or not. Two gallons of Toyota Super Long Life Coolant should do.
Thx! Where does one get that full manual? Got the sheets for Spark Plug replacement and Brake Pad replacement?
@The Big Sleaze , This is on my list to do, did you you go ahead and do it ? how did it turn out . Also regarding your question about where the service manual data come from, You can purchase a 2 day Toyota Techstream subscription and have access to all the service data online. https://techinfo.toyota.com/techInfoPortal/appmanager/t3/ti?_pageLabel=ti_whats_tis&_nfpb=true But I have to say that is very nice of @Mendel Leisk to provide this info. It takes a lot of time to download these files into local PDF files.
We've got a wiki page that has not only that link, but a bunch of good information about everything you can find there and how to make the most effective use of it, and also other ways of getting access to it. Toyota Service Information and Where To Find It | PriusChat
Did the coolant change on our 2017 at 103000KM, I wanted to use pH strips 1st to determine if the coolant was acidic but i did not find them. While I was under the car looking at all the hose I was able to remove 3 going into a a lower manifold and more coolant came out. Oily substance when I drained these bottom hoses, that might have come from the Woolwax rust proofing I did recently on the metal hose clamps. I did the fill using an OEM coolant device that creates a vacuum in the coolant system. When I the system was de-pressurized I left it for 10 min and no air leaked in. Used 1 gallon and 1/3 of the other : I did the inverter cooler the same way :