Mystery Inverter Coolant Leak from Transaxle Bellhousing

Make sure that's not rundown from resvoir O ring leak . Just be sure . Theyres a loop in transmission . Look at picture of transmission breakdown . It'll become somewhat apparent.

 

You might take a look in this video, around 34:07, to see the way the coolant passage around MG1 is supposed to be sealed off inside the bell housing.

He doesn't make it sound very hopeful for fixing a leak ... sounds like that O ring might not be an orderable part?

 

Not orderable doesn't mean not fixable. It means one has to pull out the failed one, measure it carefully, try to figure out what material it is, and order a replacement from one of the several companies that specialize in selling O-rings.

For instance, half a year ago or so my fairly old HF floor jack started leaking. They don't sell replacement parts for that model and as far as I could tell nobody else does either. Nevertheless, HF does sell packs of O-rings and one was close enough to the right size to fix the problem.

The bigger problem here is that getting to an internal O-ring in the transaxle is a much larger PITA, and the material used might be difficult to determine. So trial and error, which was an option for the floor jack, is not a great choice here.

There is an O-ring under the inverter coolant tank which is less of a problem to replace, it can be ordered, and the OP states some work was done in that vicinity. So maybe change, or at least inspect that? I know, kind of like looking for a missing key under the streetlight even though it was lost elsewhere.

Size of O-ring between Reservoir and inverter | PriusChat

 

Personally, I would do a bit more investigation. Seems strange to me that you have pink residue from dried coolant all over the place, except at the weep hole.......

VEVOR has a very nice steering endoscope that's about 90 bucks (I have one). The camera end can rotate 180 degress and look straight back from where it came. It would be ideal for sticking in that hole and looking around. The camera lens portion is 0.254" diameter so it can fit in some pretty small openings. The neck portion is like 3' long so it has plenty of reach if needed. Worse case, you may need to drill the weep hole slightly larger.

 

Regardless, plugging the weep hole would quickly take you from the desired limping to walking.

 

I missed that. Has the OP actually observed fluid leaving the weep hole?

If not perhaps stuff something absorbent, like a small piece of paper towel in there, then seal the hole with a bit of aluminum foil and tape. Drive around for a couple of minutes and then disassemble. Is the bottom of the transaxle wet without the inside of the weep hole being wet?

 

I went out to a transmission and tried to take that piece out not easy task . The o ring is like my pentaire fountain pump . But I can't get the plate out I've got the snap ring off . It just won't come out so I can measure o ring inner outer and cross . This train is not dry either it just came out of a car not been sitting a week or two

 

Prof. Kelly said he used compressed air to remove it.

He also said the O ring didn't survive that process.

From what I saw in the video, I'm not even sure how you'd get that plate reinstalled with a new O ring. I'd love to see how it's done at the factory.

 

At 35:12 in the video 3 slots are visible (well, 2 and a part of another) which were under the snap ring. They are 120 degrees apart. It looks like one could put 3 small pry bars into those slots and push down on all at once to pop off that big flat annular plug. That would be one big O-ring to go around that cap. I estimate it is about 12" in diameter, or 51 mm. The standard metric O-rings

https://www.appliedfluidpower.com/media/atlantic/pdf/Tech_Tips_Standard-O-Ring-Chart-Metric.pdf

go up to that size and have varying cross sections (1.5, 2, 2.5, 3, etc. mm) available. Probably Toyota used a standard metric size.

Is there also supposed to be an O-ring on the inside edge of the plug too? There is a groove visible at 34:33 which would line up with the inside of that cap. It isn't unreasonable that both the inside and the outside edge would need to be sealed. Doesn't mean the inside one does hold an O-ring though, it could just be a coolant channel.

As for how to install it, hopefully just seat the O-ring and then work around tapping the plug with a small rubber mallet? Either that or some crazy sort of tool to press it on.