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Size of O-ring between Reservoir and inverter

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Pinback, Jan 26, 2023.

  1. Pinback

    Pinback Member

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    G'day All,
    I have a slow leak on my Gen2 2009 that is in the inverter loop. I add a few TBL spoons of coolant each week or so. I removed the upper forward cowling to get a better look at from where the fluid might be dripping and I can see some on the front of the transaxle on the far port side (driver side in USA). I tried to get an inspection mirror in there to see more but could not see much.

    A while back I did change the inverter/transaxle coolant when I removed the inverter to do a replacement of the ABS pump (oh what fun that was, I should write up that tale of automotive woe and intrigue). Maybe I did not reseat an hose just right?

    I don't see any signs of a leak around the pump in that loop. I am not getting any error codes yet, probably because I keep the tank up to the full line. I will pull the inverter and see if I can see any better evidence.

    I am wondering if maybe the o-ring on the coolant tank has started to fail and the small drips are running across the underside of the inverter and dropping on to the transaxle. So I wondered if anyone knew what size o-ring that is so I could have one on hand to swap it out. Also, if anyone knows what the material is of that o-ring that would help too. I would guess N-Buna or EPDM or maybe silicone?

    If you don't know the answers to those questions, recommendations for a good source of onion rings in the Pasadena / LA , Ca area would also be welcome.

    Pinback

    *** "An expert is a person who has made all the mistakes that can be made in a very narrow field." – Niels Bohr
     
  2. TMR-JWAP

    TMR-JWAP Senior Member

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    This is the best I can do for onion rings :)
    Top 10 Best Onion Rings in Pasadena, CA - January 2023 - Yelp

    But, I do have a couple inverters sitting in the garage that I can pop off a reservoir and get some measurements for you this evening. I also have a few o-ring kits that I could probably match up to get you an actual "dash" size. I've ordered hundreds of o-rings through Mcmaster Carr.
     
  3. Tombukt2

    Tombukt2 Senior Member

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    Isn't that o-ring on the parts diagram no kidding. I have inverter sitting off to so I'm sure you get a measurement. I don't know what the latest and greatest o-ring material Buna and is now older there may be newer and greater materials for the latest round of rubber seals being manufactured whatever it is I would just say probably get that the latest and greatest material for the o-rings I know they're various colors and what have you for different materials air conditioning gases and whatnot so pick your poison and let it rip this is not a common place for leaks to be happening unless it's been disassembled slid back up and then it moved rolled upon offering up the pieces kind of common that's why a lot of o-ring situations the o-ring or the part slipping into the tube that the o-ring is housed and has to be lubricated slipped in at a perfect 90° or perfectly straight no wobbling that sort of thing.
     
  4. Mendel Leisk

    Mendel Leisk Patron saint of newly poured sidewalks

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    This.
     
  5. TMR-JWAP

    TMR-JWAP Senior Member

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    I'm sure it has a Toyota part number for it. Whether it has the dash size is another question. I would suspect a single Toyota packaged o-ring would cost about as much as a 100 pack from Mcmaster.

    BUNA-N is still probably the overall Champion of the World for general use with oils and glycol.
     
    #5 TMR-JWAP, Jan 26, 2023
    Last edited: Jan 26, 2023
  6. Mendel Leisk

    Mendel Leisk Patron saint of newly poured sidewalks

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    First and last time I needed to know an o-ring size was for my Moroso oil cans. Moroso rep sent me this:

    We do not list a replacement o-ring for that, but we do have them in our warehouse. You would need to call us direct if you wanted to get one ordered, or you can source an o-ring with the same specs; 2.614" I.D., .070" thick in Buna-N. What you saw on the threads of the catch can was anti-seize, we would recommend applying more to keep the top and bottom halves from seizing together over time. It is possible the o-ring was stretched or pinched upon reinstallation.

    But yeah, if you're in LA, just pick one up at Toyota Dealership parts department? You don't need a parts number; they'll look it up for you. But it doesn't hurt to check first, say at parts.toyota.com, get the part number, and see if the parts guy comes up with the same number.
     
  7. ChapmanF

    ChapmanF Senior Member

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    Indeed, the Toyota one is $7.44 list, though some dealers may discount.

    You could probably save a few entire dollars by spending, say, an hour of your time researching the O ring dimensions and material compatibility, and then finding a source for a hundred pack of those, and maybe shopping for a while for some other stuff to make up a minimum order to get free shipping or something.

    And then you'd be left with ninety-nine O rings you didn't want.
     
  8. Mendel Leisk

    Mendel Leisk Patron saint of newly poured sidewalks

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    In my case the automotive retailer I dealt with said they could get the o-rings, but required a minimum order of 20. Think it was around $20. It made sense in my case, because the OCC O-rings are fragile, subject to wear and tear. But yeah, in OP's shoes I'd just contact dealership parts department.
     

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  9. TMR-JWAP

    TMR-JWAP Senior Member

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    Tombukt2 likes this.
  10. Pinback

    Pinback Member

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    Thanks Chapman and TMR-JWAP for pointing out the part number. Previously I looked right by it on the parts diagram.
    And sorry for the delay in getting back to y'all, something came up at work and I have been a bit distracted for a few weeks.

    It still would be helpful to know what size it is before I take apart the system so I can know if I have one on hand. I keep lots of standard dash sizes as well as many metric sizes around in Buna-N and EPDM (I use these in water systems in preference to Buna) and a few sizes in silicone. But I don't stock every size. I do order from McMaster often. They are amazing at how fast they deliver.

    So far I have just been adding ~ 50mL (almost 1/4 cup) every 10 days or so. But I really want to find the leak.
    I am thinking I might try cleaning up the place where I find the fluid and the areas below it to where it drips once it builds up. Then use the cooling system pressure tester @ 5.4psi to see if I can see the leak in action. (5.4 psi is within the range for the cap and what the service manual recommends using to look for leaks.)

    Any suggestions, cautions, warnings, insights etc on this?

    Pinback
     
  11. Tombukt2

    Tombukt2 Senior Member

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    With the supply like that you should have something that was pretty easily work so I wouldn't worry about it pull it apart see what you got or what you don't have and you'll fab something up squeeze something down to make it fit whatever I mean I've got one here I can just pull off if you want you want me to just measure it the o-ring diameter circumference what have you I have calipers here
     
  12. Pinback

    Pinback Member

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    Actually, if you do have a chance to make some measurements that would be great. My on hand selection of metric o-rings is not as diverse as I would like. And I noted today that much of it is 10+ years old which in LA means even though they are in a sealed set of ziplock bags, they will be somewhat compromised. And I will be ordering some other bits and bobs from McMaster shortly so adding a bag of the right size, if needed, would be simple.

    However, I have a bigger concern as I look at where the coolant is puddling on top of the transaxle case. It seems to be near a seam between the case housings. Replacing the seal between those is not a job I want to think about. If the fluid were just leaking out of the car that would be bad enough, but could it also be seeping into the oil in the transaxle? I am not familiar with the cross section of the the housing parts to know if that would be a problem. It seems worth investigating. My next scheduled trans fluid change is a while off in the future. Maybe I will do it prematurely to answer that question before serious damage is done to the internals.

    Pinback

    *** "If we knew what it was we were doing, it would not be called research, would it?"- Albert Einstein
     
  13. pasadena_commut

    pasadena_commut Senior Member

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    Lucky Boy at 618 S. Arroyo Pkwy in Pasadena, especially if "good" weights "quantity" highly. They used to serve onion rings in a brown paper bag, like a lunch sack, which would invariably have soaked through with oil if I took it home. Enough greasy crunchy onion rings to make a cardiologist faint. Best to bring some extra mouths and eat them on the spot. They tasted good too. Caveat - I have not been in many years so I cannot vouch for those rings now.
     
    Pinback likes this.
  14. Pinback

    Pinback Member

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    Oh yeah I forgot about Lucky Boy! I think many years ago they were on Walnut not too far from the court house and library.
    Thanks for the reminder! I eat very little meat anymore so I don't go to burger places that often, hence my request for insights on where to go.
    I'll be sure to take some Lipitor and Beano when I visit! LOL

    Pinback
     
  15. Pinback

    Pinback Member

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    Quick update: I no longer need the O-Ring size. It is not that connection where the leak is happening. It seems to be the MOTOR WATER JACKET COVER plate and associated bolts that are leaking There may be a crack in the plate too. This plate is held in with 6 bolts and sealed shut with FIPG (Form In Place Gasket) ThreeBond 1281 or Toyota Genuine Seal Packing 1281. I suspect the FIPG has failed. It is a mess with lots of pink and white residue typical of the SLLC after evaporation. As soon as the parts arrive and I have dry weather on a weekend, I'll get the inverter all the way off and do a proper repair and cleaning. I am just hoping I don't also find cracks in the transaxle housing. There is residue in all the nooks and crannies of the housing "down hill" of that plate. Also off to the port side around the motor mount.

    I pressurized the loop with a hand pump and a cooling system servicing kit I have. I ran it to 5-5.5 PSI. Initially, I thought I saw fluid oozing out from under the plate and the pressure would drop quickly. (under a minute) but then I could not verify fluid flow visually and the pressure held for over 15 minutes.

    To do the inspection, I disconnected the 12V battery and pulled the HV safety plug of the traction battery. Then I removed all the electrical connections to the inverter and found some blocks of wood to raise it about 3.5" (89-90mm) while leaving the coolant hoses connected. This gave me a much better view of the mess.

    Pinback

    **** "Yeah, well to you it's a pile of inter correlated coordinates. Fine. But, to me, it's a target. And NOTHING makes me happier than a target. " Lt. Doolittle
     
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