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Just got a call from one of the eevc members in Pennslyvania. She has a highlander hybrid with 102k miles on it and the inverter/planetary gearset has apparently failed. The vehicle was trouble free up till now and was just taken on a road trip to Baltimore. The vehicle died in her driveway, she turned the key put it in drive and it rolled backwards. Toyota is quoting 8200 bucks for the repair. She is fighting toyota to try to get them to cover it and has found a used inverter on ebay from a wrecked highlander hybrid for 800 bucks if toyota does not come through. I asked her if she remembers hitting anything but she does not remember that happening. Not sure yet if fluid was ever changed. I will update when I find out more.

So what has failed -- the inverter, transaxle (where the planetary gearset is housed), or both? They're separate units.

Hi Jim:

__Jesse called me this morning and he is trying to find out more details as we speak. He knows the lady that owns the HiHy but has not spoken to her directly.

___I am very interested as well.

___Jesse passed on that Al (Hobbit) was talking about MGSet fluid/coolant change out??? I will have to look at my parents Owners Manual to see if there is some kind of fluid change schedule for that. Could you look it up in yours and see if there is something in your -II as well?

___Good Luck

___Wayne

Inverter (and engine) coolant replacement interval is 100K miles/ 10 years for the 2005 Prius.

Jesse, I would encourage her to insist on the codes that led the dealership to whatever diagnosis they made. There are stories of dealers taking the replace-parts-until-something-finally-fixes-the-problem approach, at considerable and often unnecessary expense to the owner. Post the codes here and on the Toyota forums (including PriusChat -- some there are HiHy owners too) and you should get some good feedback on possible causes, reasonable repair prices, and repair options (such as salvage parts).

I don't follow threads reporting major HSD repairs as closely as some (although I probably should as my car approaches the end of its warranty), but IIRC, transaxle failures (relatively rare in the G-II) are accompanied by warning signs (noises, vibrations, whatever) before outright vehicle failure. I don't remember what symptoms accompany (even rarer) inverter failures.

What year HiHy was it? The Canadian 2008 needs engine and inverter coolant changed at 80k miles then every 40k after that.

Jesse and I have been vaguely tracking/wondering about the
transaxle fluid change intervals in a number of vehicles, including
the FEH which we haven't even determined if it has a drain plug
yet. The Prius tech community considered used-oil analyses for
the ATF-WS and figured that it's prudent to get it out of there
around 50,000 which I did in mine; having just topped 100K it's
about time to do it again. Bottom line is that the maintenance
schedule doesn't necessarily match owner-community "street wisdom"...
.
_H*

Bottom line is that the maintenance
schedule doesn't necessarily match owner-community "street wisdom"...

True enough. I'm in the process as we speak of gathering the tools and supplies to change my transaxle fluid, now with 58K miles on it. However, has anyone found evidence of a need to change coolant before the recommended interval in the Toyota hybrids?

True enough. I'm in the process as we speak of gathering the tools and supplies to change my transaxle fluid, now with 58K miles on it. However, has anyone found evidence of a need to change coolant before the recommended interval in the Toyota hybrids?

I'm about to do my first transaxle drain/refill, too, at about 49k. Once I've decided that I can do mine without screwing it up I'll do the wife's which just ticked over 60k.

I would be surprised if changing the coolant early would do much. It isn't subject to the same kind of environment, and there is less to go wrong if there is a bit of chemical instability.

Alternatively, I have been thinking about a little data mining project on inverter coolant pump failures. It's an inexpensive part relative to the inverter itself, and I have always considered water pumps to be a wear item. It would be nice to get a feel for when they start to go bad in the event that a particularly maintenance-conscious owner wanted to do a pre-emptive replacement. Considering how cheap this vehicle is to run, I wouldn't feel bad about replacing a $150 item to protect the $1500 item.

Hi Tim:

___Have you heard of "any" Prius-II, HiHY or RXh coolant pump failures? Toyota is pretty good about fluids after the Camry sludge debacle. If coolant has an 80K life, it should work darn well out to 80K and with Toyota's past predicted reliability, 100K should have been be a given for the HiHy in question?

___I am very interested in how this all works out...

___Good Luck

___Wayne

ICE coolant pump failures, 3-4. Inverter coolant pump failures, yes, more than I would think normal for Toyota. The inverter coolant passages, as documented by Hobbit, are convoluted and seem the gather "gunk" at some points. The inverter works all the time as opposed to the ICE. An inverter coolant change earlier might not be a bad idea.

Wayne

Hi Wayne:

___Since I have a Prius-III in the family, have you seen any drain plugs or the procedure in the service manual yet?

___Thanks in advance.

___Wayne

Well, in all honesty I haven't changed any of my coolants yet
at > 100K miles. One obstacle is wondering where I'd most
appropriately dispose of the old stuff. I did drain a little
from the various points in the engine system, and it's as pink as
the day it went in. This may or may not be any indication of its
continuing viability, but there's certainly no obvious evidence of
corrosive effects that I could detect. I'm looking for where I can
get small quantities of those dip-strips for testing coolant and
brake fluid that wouldn't have me spending $70 or so for a whole
bottle of the things.
.
I'm very aware of the sound of my inverter coolant pump running,
and no apparent problems so far. There have been several documented
failures but it's actually a quite well-designed brushless-DC
unit so some of those may have been corner cases. That coolant
is still nice and pink too... and I've recently been watching my
inverter temps and it's amazing how fast they drop *down* once
high currents cease being sent to the attached motors. I'd say
just from that that there's no obstruction in my system.
.
_H*

Toyota ends up covering the 8500 dollar plus repair bill. More info soooon!!!

Toyota ends up covering the 8500 dollar plus repair bill. More info soooon!!!


Very good to read this. :)

Toyota often does cover such hybrid issues and I am glad no exception here.

For coolant disoposal, inquire at radiator shops. Many will recycle it. Or at least say so :)

All Toyota (etc.) drivers with liquid-cooled electronics ought to train themselves on how to confirm correct fluid pumping by visual inspection of the top reservoir. AFAIK it is in none of the vehcle owners' manulas, but widely posted on the internet.

If someone knows details on the NHW20Prius coolant pump redesign sometime during the model run, please post them? I cannot find that.

DAS