Ideas for coolant change to eliminate possibility of air pockets.

I suspect you'd have new coolant running out the drain while a lot of old coolant is still in the system.

Could the "high-tech" method used on your truck have involved a vacuum pump? As I understand, that's essentially how cooling systems are filled on the assembly line, where they have to add all the coolant fast, with no time to chase trapped bubbles of air.

 

Some info here:

About to tackle the inverter and radiator coolant | PriusChat

I've changed coolant on Hondas for decades. But I'm hearing it's more involved with Prius? For starters due to two circuits? Plus headaches purging air?

With Honda, it was basically drain (rad and engine block), fill with vent bolt open 'till it overflows, close vent bolt and continue filling, 'till it's up to the rad neck.

Then run the car with rad cap off, with a baster and container at the ready. When level climbs in the neck baste it off, when it drops, add it back. Maybe squeeze the accessible hoses a bit as it's going.

Carry on 'till the cooling fan's come on twice, then shut down, rad cap on, drain, clean and refill the overflow bottle.

 

I've seen some clever ideas for making a low-cost vacuum pump on Youtube! Might make an interesting and useful little project?

vacuum pump - YouTube

 

The straight repair-manual method for the engine coolant on my Gen 3 was so easy and worked so well that I put aside all earlier thoughts of trying to outsmart it. Pour into the reservoir with the bleed valve open, until the reservoir is full to the B mark and some coolant comes out the valve, close the valve, start and warm up the engine, shut down, observe that the level has dropped from right at B exactly down to right at MAX, think to self "all right, the engineers got that process pretty well dialed in", call it a day.

-Chap

 

Toyota eliminated the bleed bolt in 2012, assuming you're talking about the one atop EGR stuff. I think you could still just pull one hose off there, pour in fresh fluid, and reconnect the hose once coolant reaches it.

Fwiw @NutzAboutBolts has a video on coolant change, it's a 2012, Without engine coolant bleed bolt, but it didn't seem to matter.

 

I bought one of these, it works great.

Not only does it eliminate trapped air it leak checks the system and fills in a couple of minutes.

 

This.

The turd gen engine loop is as quick and easy as any I've ever changed, and really can't imagine a mechanical aid making it any easier. Even the open bleed valve is optional as the valve was done away with in later turd gen years, maybe as early as the 2011 model but don't quote that... Gen 2, on the other hand, is tedious and time consuming. Any of the coolant change aids would likely make that deal a little less frustrating/time consuming.

 

How hard is it to change coolant on Gen 3 Inverter? The Gen 2 has to be bled also.

 

It looks pretty easy in nutzaboutbolts videos. I'll avoid the "@" symbol, I think he's tiring from putting likes on all my posts.

 

Lol it never gets old, keep it up

 

Changing the inverter coolant is way easier than changing the engine coolant since you don’t need to run the engine to bleed the air out. You just gotta cycle the inverter a couple of times to bleed the air out of the system and you’re done.

 

We are seeing four generations of Prii here now and some procedures have changed. I have experience with Gen 2 and now own a Gen 4 and most haven't touched it yet. I hope Toyota just keeps it simple.

 

I wonder if anyone will put together a 4th Gen Repair Manual, or is it even possible any more?

 

Too bad I don’t get a free Prius for every year, or else I would upload all the videos of them lol