DIY Coolant Change

Engine coolant easy but inverter tricky because you cannot let the coolant drain all the way otherwise you will have air in system,it's a two person job

 

I did both engine coolant and inverter coolant on my old Gen 3 Prius by myself and had no problems. There is a PDF floating around on how to properly do it. Drained everything from the bottom of the vehicle and then just added new coolant to both. For the engine coolant if I remember, I had to monitor that over a few miles as it didn't change much until the motor was hot. As for the inverter, I filled it to the top, turned the car on, could hear the inverter pump spin for about three seconds and then shut it off. Added more and kept doing it til it didn't move anymore. It was a bit ago that I did it so please still look it up.

 

I've done Honda coolant changes for donkey's years, very straightforward. You drain, both radiator and engine block, then fill with the air-bleed valve open 'till coolant comes out, then shut it and continue filling to the radiator neck. Then start the car and let it run with the radiator cap off, until the cooling fan has come on twice. During this process you occasionally will need to baste off coolant as it comes near to overflowing the radiator neck. Then it may drop down, and you baste it back in. After the fan cycles on twice, your're done. Never any issues.

I've read with Prius in particular it's a bit more difficult, due to the separate inverter circuit (twice the work) and getting air pockets out is not as easy. It's also a little unnerving: there's no damn cap on the radiator, lol. When it comes time for us, I might just let the dealership do it.

What km's are you at? The maintenance schedule says 160,000 km's or 120 months (10 years), then 80,000 km's or 60 months.

 

I have them, fwiw. One thing I've heard: removing the the engine block drain bolt not much comes out. That would be the opposite of my Honda experience. Also, some recently disconnected one of the coolant hoses at the exhaust gas recirculation apparatus, and got a fair bit out there.

 

This is not my experience Gen 2 or 3. Inverter loop is drain, fill, and READY/OFF the car (as PlumbersCrack says) while topping the coolant and listening for the pump to settle down. Gen 3 is even easier than 2 since you don't have to rig a hose from the bleeder to the bottle. It simply bleeds itself using the pump to circulate. No bleeder valve involved that I recall.

ICE loop is as easy as any other I've ever done. I think the fear is provoked by Gen 2 and the overly complex part the 3-way valve/thermos play. That circuit is for sure a pain in the nice person but only in that it's tedious and time consuming. With Gen 3, refill to the F line with bleed valve open, bring it up to temp in inspection mode with the heat cranking and burp the lower hose several times. Once you've got it stabilzed and topped off, you're good. You may add (or baste out!) an ounce or so after the car's been run on the road a few times to get it OCD perfect. You'll be glad you didn't pay to have it done. I followed the PDF's you posted.

There is a "high point" bleed valve directly over the EGR ''radiator." Open it up while refilling. Den49 covers this with a pic in this thread:

Coolant Replacement Interval | PriusChat

I don't ever measure how much fluid I ever drain from anything but I'm quite sure you'll do the inverter with just under a gallon and the engine with somewhere between 1 1/2 and 2 depending on how crazy you go with the draining. I don't believe you need to drain every drop or do a flush given the high quality coolant.

I'm going to say you do have to pull the stinkin' undertray, and that's the worst part of the job, IMO. The inverter drain doesn't line up with any of the ports in the tray. It looks like you could probably manage to pull the plug with the tray in place but you'd be dumping coolant onto the tray. Also, it would make it hard to burp the lower hose unless you're really tiny and could wedge your arm between the tray and oil pan via the oil change trap door. I'm always tempted to leave the tray off. My oil change trap door broke off several changes ago and it's been a great mod!

True, my OCD wasn't pacified by the trickle from the block drain. I won't go near it next time. I did not pull the hose at the exhaust recirc but it sounds like a good idea. Wouldn't be surprised if a worthy amount was hiding out down there.

 

Best tool to eliminate the time needed to bleed air from the system(s): UView 550000 Airlift Cooling System Leak Checker and Airlock Purge Tool Kit. It works.

2 gallons of premix (with some left over) when doing both ICE and inverter.

 

+1 on the Airlift device. Use your air compressor to pull a vacuum and the coolant change does become a drain and fill, both engine and inverter.

 

No air compressor here.

 

How about the Lisle Funnel?

 

I bought a cheap air compressor from Harbor Freight a few years ago for about $100. It works fine for the light duty that I use around the house. Keeping tire pressures set, blowing off my riding lawn mower, etc.

 

If changing the inverter coolant, don't forget about replacing the drain plug gasket. It's an aluminum crush washer, Toyota part number 90430-A0003.

 

Any recommendation? I wouldn't know where to begin.

For cleaning off lawn mower I use a corded B&D leaf blower. That works good.

 

The one I have is a Central Pneumatic, 2 HP, 8 gallon unit.

A leaf blower works well but does not get to tight places as well as an air nozzle.

 

I just changed coolant in ICE using Airlift UVIEW to refill coolant and it worked great for first time for me using such a device. (It did take a while to drain radiator)

OnePlus One?

 

Its about $100 for a compressor and another $100 for the Airlift tool. These are 120K mile fluid changes. For a do-it-yourselfer, you'll spend more time ordering and figuring out the Airlift tool than you'll spend bleeding out your cooling systems. I'm told it only takes about 15 minutes to fill and bleed the engine coolant and ten for the inverter coolant... The NutzAboutBolts guys show that it's pretty easy to do these procedures with out an AirLift.

I'm not trying to put down the product, just point out that it's fairly expensive for a tool to quicken a do-it-yourself project that you perform only once every 120K miles.

 

For a single vehicle and 120K mile intervals I would tend to agree with you.

I have multiple vehicles and I do 50K mile intervals so it is worth it to me..