tricks for coolant change on 2020 Primes?

Toyota coolant is an extended life coolant - good for 100K; but double check your maintenance manual. I know mine isn't due til 100K.

You will need to "burp" it. A pressurized coolant swap is the fastest and easiest way of doing this; but the equipment cost is too much. A simple drain and fill will require a lot of "burping" and checking levels for the next few months to ensure you got all the air out.

 

It sounds as if they made it extra complicated in Gen 4 somehow.

In my Gen 3, the coolant reservoir has a line marked "B" that is up above the "F" line. When replacing coolant, you fill it to "B", then run the engine up to temperature and for several minutes longer, shaking the hoses some, then shut it off and wait for it to cool. When it's completely cool, you check that the level dropped from "B" down to "F"; if it did, you got all the air out.

 

The system needs to be put in maintenance mode and is pretty tedious.

I prefer to use the Uview Airlift system. No need to put the car into any maintenance mode or even turn the car on. Just drain the coolant and use the airlift system and you're done in 20 minutes.

 

Repair Manual info:

 

Still prefer the quick 20 minute change with the air lift system.

 

I'm thinking it'll just be a matter of time before somebody gets second thoughts about that choice of wording.

 

Don't mean to dis' it, just adding to the info.

 

I have one of those systems and used it a couple times, then went back to doing it the way in the manual, which is pretty straightforward for Gen 3 and has never given me any trouble.

The vacuum refill is more like a magic trick that takes 20 minutes just to set up (including, if you're me, dragging out an air compressor to power the vacuum venturi, because I don't just have a garage with a fixed compressor ready in the corner), getting ready for that matter of seconds where you finally say abracdabra and it all works like a charm.

But you do have to get the setup just right. Make sure the supply jug of coolant is higher than the highest point in the system, and the tube that will slurp it out is down to the bottom, and there's enough in the jug to complete the fill in one go, and you get all your tubing filled with coolant and free of air before you start.

If you get a partial fill on the first try, you can't just pull more vacuum and finish the job; the hoses will collapse again, and the coolant from your first partial fill ends up getting sprayed out of the venturi. It's a drain again and start over deal.

It is undeniably fun when it all goes right.

 

This gentleman does a wonderful job.

 

One opportunity I think he sort of missed in that video would have been to say "I'm a Toyota master diagnostic tech, so I am familiar with how the manual says to do this, and you'll notice the method I'm showing you is different here and here, and that's because I think those changes make it better because explanation here." That way the viewer comes away both understanding how Toyota says to do it and how this guy does it, and understanding the reasons behind his changes.

 

Toyota, like most other organizations, have the, "It didn't come from here." attitude.

The procedure provides for maximum profit for the dealership.

Check out the official Toyota method for transmission fluid level adjustment.

 

There seem to be a lot of takeaways possible from that video:

1. Some dipstick's original decision to build automatic transmissions without dipsticks created a lot of follow-on headaches for everybody.
2. The "we'll solve that with a drain plug that has a calibrated-height straw" was pretty clever, but calibrating the height for some nutty fluid temperature that's well above ambient but well below operating was kind of facepalm-worthy, wasting dealer time waiting for the fluid temperature to cool into the magic range.
3. When Toyota realized those decisions had created headaches and wrong outcomes, they did go back to the drawing board and solve that problem. The solution is tool-heavy, but it does give shops a way to do the job quickly and correctly at operating temperature, without all the lost time and money waiting for the temperature to drop.
4. Their final solution, with an adjustable straw, fill plug adapter, and low-inch-Hg vacuum source, is comically Rube Goldberg, but also pretty much the one workable idea they had left in the corner they'd painted themselves into with (1) and (2).
5. Because of (4), there really aren't going to be good alternatives to it (other than the old, time-consuming way, wait for the fluid to cool to the lower temperature). Anybody claiming to have a fast way of checking the level without using the special tooling is likely just doing it wrong.
6. It is possible to make a video that shows the technical grounds for why something is done a certain way. Prof. Kelly shows how it's done, again.

I can think of one other solution they could have found in the corner they were painted into: release a revised drain-plug-straw in some whole new color (fluorescent green maybe) and the correct height for normal operating temperature. Instead of checking fluid levels, dealers would be instructed to drain, replace the straw with the new one, then fill to the height of the new straw at operating temperature, and slap some big "has new straw" label on the transmission pan.

That way would require less specialized tooling, and be more DIY-friendly, but the Rube Goldberg way probably is faster for the dealers, once they have the Rube Goldberg tools.

... (7) I'm sure glad no Prius transmission is like the one in that video.

 

Even simpler would be to make a chart calculated from the information from Techstream of the additional height increase of the stand pipe for each model of transmission at normal operating temperature and make a kit of specific length color coated insert tubes that friction fit into the top of the OEM tube.

An aftermarket specialty tool manufacturer like Lisle or OTC see a good market opportunity.

 

Prius level check is dead simple though. And isn't this thread just fourth gen coolant changes??

 

The thread sort of zagged onto "alternative service methods seen on youtube, and justifications thereof." Happens sometimes.

 

Hey, zagmeister here…

 

I was thinking the same thing as I watched that video. I'm guessing that the height of that straw was most likely calculated by the same people who designed the interface on the 11.6" display.

 

Maybe they just bought a whole bunch of straws the same height, and in different transmission models they just calculated the fluid temperature needed for that height to be the right level....