Inverter coolant loop still overheating...at a loss

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by AnotherGen2, Jun 29, 2022.

  1. AnotherGen2

    AnotherGen2 New Member

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    New to me 08 Prius. I typically clean, repair, and replace all items I can when I acquire a new vehicle. Hybrid battery fan blades, air filters, etc. Recently replaced inverter coolant pump with a flush and fill as well, after getting a P0A93.

    Another hot day (100°F and high UV in CO.) today, and lo and behold my ice cold AC starts cutting on and off again. Mostly off. I've bled the loop properly thrice, and can't seem to get any more air out of it. No leaks, levels are good. Coolant is turbulent in the reservoir. Electric fans seem to be working. My next plan of attack is to remove front bumper and inspect radiator and condenser more closely.

    What else can I do?
     
  2. TMR-JWAP

    TMR-JWAP Senior Member

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    A P0A93 is a cooling performance problem. It also has 2 possible subcodes to point you in the direction of either a pump problem or a fan problem. Do you know which one you had?
    90% of the time, it's a pump problem. Based on your post, you've covered most of that. All you don't know for certain is whether you may have a clogged coolant channel or something similar in the inverter itself.
    Do you have a contact pyrometer that you could check hose or pump temperatures? ie...Is the coolant actually getting too hot, or is it just a temp sensor in the inverter sensing a localized hot spot?
    Any chance a hose is routed incorrectly? or kinked? Has the inverter ever been removed or replaced?

    If the coolant is getting hot, then I think you're going in the right direction. Make certain you have adequate air flow at the heat exchanger.
     
  3. Tombukt2

    Tombukt2 Senior Member

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    I keep going through inverter pumps no matter what manufacturer they all look the same same bracket so I'm taking one of the pumps from another car that goes from the coolant reservoir in the fender the metal jug is a little pump sitting next to it and the same kind of pump sits next to the brake actuator or in between the brake actuator and the brake master cylinder or whatever those two pieces are there's another pump just like in the fender well sitting there. I have both of these in my hand they're both the same same connector same connector as the inverter coolant pump and these round pumps that look like a spa pump or whatever they really pump and they don't seem to fail this design so I'm going to put one of these where the inverter coolant pump goes and see if that helps because every one of these things I put in new use doesn't matter just stops working. Does the car just randomly shut the inverter pump off seemingly I don't think so The fuse is good when the car is running and I pulled the fuse by the AM2 or whatever the car engine stops running and it surely codes then with the same code being discussed here
     
  4. SFO

    SFO Senior Member

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    Welcome to PriusChat!!
    Was the replacement a toyota oem pump from the dealership, or something else?

    FYI : you're moderated until you've posted 5 times.
     
  5. TMR-JWAP

    TMR-JWAP Senior Member

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    That's strange, because I've swapped inverter coolant pumps on a couple dozen Gen 2s and never had a follow-on failure, yet. I keep 2 or 3 on the shelf at all times.
     
  6. Tombukt2

    Tombukt2 Senior Member

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    I just moved the pump that goes in the fender well that pumps out the coolant metal tank looks like a little spa pump I just took one of those and put it where my inverter pump goes and now the inverter fluid will almost jump out of the tank. I think any overheat problems have just been mitigated this pump is moving the water and I have no reason to believe that these 14 volt mini looking spa pump looking things will fail the ones that all of them I've seen in checked are working great even if they're a tad loud they're still working so we'll see
     
  7. PriusCamper

    PriusCamper Senior Member

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    The engine and hybrid cooling system is not related to how well your AC works... But a weak hybrid battery on a super hot day can limit how well your AC works. It's one of the things I like best about having a Project Lithium battery and if you buy one with my affiliate link I can offer you unlimited tech support: https://projectlithium.com/?ref=9qLPw AC performance on a super hot day is hugely improved with a Lithium pack.

    Beyond that, it might be time to take your A/C into a shop that has an expensive machine that sucks out your refrigerant and lubricant and precisely measure by weight to make sure everything is at spec and fine tuned. Because AC is a variable pressure system it's not a DIY project for 99% of us.
     
  8. TMR-JWAP

    TMR-JWAP Senior Member

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    One of the very early symptoms of a failing/failed inverter cooling pump is intermittent AC due to inverter temperature, even if it's not hot enough to trigger a fault code. Maybe that's an experiment I'll try soon. Find out exactly what temperature the AC shuts down when inverter is getting abnormally warm. Shouldn't be too hard to do. I'll have to get my kid play driver while I play with the computer.
     
  9. Tombukt2

    Tombukt2 Senior Member

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    I experienced this very thing yesterday and knew exactly what was wrong as soon as I noticed the air going out and the triangle come on I knew my inverter pump wasn't working and it wasn't
     
  10. SFO

    SFO Senior Member

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    Product link? :whistle:
     
  11. Tombukt2

    Tombukt2 Senior Member

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    Uhh I will have to look that up and see if I can find you a part number or I'll look on the part itself it's a denso pump there's one in the fender well of all Gen 2's pumping the stuff out of that nice stainless steel coolant tank and then on many there's one in between the two brake parts right up there basically behind the speedometer under the wipers so there's two of them on the car I just took one off one of my junk cars particular one I took was in the left fender well behind the fender liner right there at the tank move the fender liner turn the wheel take a 10 mm bolt loose slip off the hoses I moved that to where the inverter pump used to be Right now it's just hanging I'm going to put it in some foam in the next day or so I'm just trying to make sure it's not the car cutting the pump off or something it's causing this problem
     
  12. Tombukt2

    Tombukt2 Senior Member

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    Okay so since the new pump has been spliced in correct flow maintained the center of a pump is generally the suction in the discharges right or left or center up Not the direction of the pump anyway I work with pumps all day. Now the inverter doesn't even get warm I could lay my face on it like a pillow my cheek no problem before it was warm where that would be uncomfortable could put my hand on it but not lay the side of my face on it. And what's even weirder about this is since I did this like yesterday early in the morning I had to fill up the car about an hour after I was finished since I filled up the car I am seeing mileage like 51.8 and all kinds of nonsense like that 52 50.3 all of this I have never seen anything like this mileage on this display in this car since I got it in good condition right before the pandemic generally this car showed 45.2 on average so I'm just not understanding nothing else has happened other than I fixed the brake actuator changed it but nothing else has changed in the car and not the same type of fuel nothing My brakes weren't dragging or causing me to lose mileage the car rolled fine it just had brake lights on and the brakes worked. So I'm not sure why all of a sudden seeing this increase in mileage on my display it's like five or six miles above the norm and I just noticed it because I watch it every so often I just think it's weird and my inverter is not even getting warm to the touch which before it would and without the pump when the pump was broken oh yeah it got 185°. Not for long but it got up to that temp.
     
  13. AnotherGen2

    AnotherGen2 New Member

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    You are actually completely incorrect on this, perhaps on purpose to mislead me and shill me your battery that you get a kickback on.

    As TMR said, the computer will shut down the electric AC compressor when the inverter coolant loop is overheating, or nearly overheating to help bring temperatures down.
     
  14. AnotherGen2

    AnotherGen2 New Member

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    If you are curious, I have the problem solved. A dirty, clogged radiator with many bent cooling fins is the culprit. I did two rounds of soaking and pressure washing with Web Condenser Coil Cleaner. I straightened as many bent fins as I could.

    This clearly highlights one major design/engineering flaw with the gen two that always bugged me. The inverter coolant loop uses the BOTTOM 1/3 of the radiator, as opposed to the TOP.

    And the bottom 1/3 of the radiator is precisely where all the bent fins were, where all the pebbles and other debris were. I'm sure the engine could survive easily with only half of it's radiator clogged and dirty, but the inverter loop obviously cannot abide its entire radiator blocked.
     
  15. Tombukt2

    Tombukt2 Senior Member

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    Yes I keep mine whistle clean and silver. And I clean it twice a year just like my heat pump coils.
     
  16. AnotherGen2

    AnotherGen2 New Member

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    Even more important with the Prius than non hybrid ice autos. As you see here with my new purchase.
     
  17. Tombukt2

    Tombukt2 Senior Member

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    I knew the radiator was divided up it also looks like it's really well made so if we use care and keep it up . Should be good.
     
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