Engine temperature warning

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by TechnicalGeek, Nov 6, 2020.

  1. TechnicalGeek

    TechnicalGeek New Member

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    Good morning priusers! I have a 2015 Prius two and its been excellent. I do all my own oil changes and I have been loving the car since I got it more than 2 years ago. It currently has 159k miles on it.

    I wanted to pick the hive mind and I have already searched this forum for the issue but all the similar posts referred to the Triangle warning which I am not seeing. Here's whats happening:

    Wednesday when I was driving home, I noticed the Engine cooling temperature warning light come on, It stayed on for about 15 seconds then went off. I immediately pulled over and popped the hood. Noticed no steam and noticed nothing out of the ordinary I searched all over using a flashlight looking for leaks etc. The only thing that was amiss was the coolant level on the reservoir for the Inverter coolant was lower than the low mark. I immediately went to the wal mart and bought new coolant (50/50) and waited for the engine to cool and added it to the full mark. I also changed the oil since I was due up for it anyway.
    The next day (yesterday) I drove to my dental appointment and noticed the light come on again. And then immediately go out. (about 15 seconds). The light didn't come on any more at all yesterday after having drove a good 100+ miles.
    I already have a Veepak bluetooth OBD2 reader installed so I downloaded a new app to read it while the car is on. I monitored the temperature continually. This is Engine temperature though and as far as I can tell the inverter coolant temperature is not on this app (it may be a paid version option, I will have to dig into this when I get back to my car after work) When I drove it all day yesterday and also on the way into work today the most it got to was 91C when climbing hills and it would cool off down to 81C normally. The light has not come on since yesterday morning.

    So far what I have read on here is, it could be an inverter pump, as I do not see any leaks. I will continue to monitor it using the app, if the light does come back on *knock on wood. Honestly I am in NO position to be spending any money on anything and yet I need my car for work I am stuck in between a rock and a hard place if this needs repaired, in these difficult times. I do plan on doing a radiator flush and full tune up when I get my tax return next year but now money is so tight I am living on a razor edge.
     
  2. TechnicalGeek

    TechnicalGeek New Member

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    I am sorry I misread I do not have a Prius V - this should not be in the V folder.
     
  3. Mendel Leisk

    Mendel Leisk Sunday driver DIY’r

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    You can report your post, ask the mod to move.

    Have you ever cleaned the EGR (Exhaust Gas Recirculation) circuit and intake manifold?
     
  4. jerrymildred

    jerrymildred Senior Member

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    Welcome.

    The inverter coolant level has nothing to do with the engine temperature.

    YIKES!!! If you actually added something other than Toyota SLLC to the inverter system, you might want to rinse that out and put in the correct coolant immediately.

    This is because you apparently haven't addressed the engine coolant issue. Check that level and if it's low, as would be expected, look for leaks. The engine coolant pump is the most likely place to leak. You'll see pink drips splattered in that area.
     
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  5. Peter123

    Peter123 Active Member

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    I would look at the water pump. If it is failing, you would get the temperature warning. Replacement pumps can be ordered from rockauto.com. Look for the Aisin pump. It is the OEM that Toyota buys pumps from. There is a separate cooling system for the Hybrid Inverter. It has its own pump. But this sounds like a main water pump problem. And either use Toyota Brand or Aisin coolant.
     
  6. TechnicalGeek

    TechnicalGeek New Member

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    Thank you
    Wow ok I added the mixture I thought it was the same - Have not had any issues but I was just going off old posts in this forum. How hard is it to flush that now? Lord I don't need any headaches

    I will look again but I didn't see any evidence of a leak anywhere. I drove it yesterday and had no warning lights on the dash and the temp didnt get above 95C - The air temps here have been in the low 70s

    Another culprit could be a fan - I read where the fan may not be kicking on
     
  7. TechnicalGeek

    TechnicalGeek New Member

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    Also do you know if there are two different pumps one for the engine coolant and one for the inverter coolant?
     
  8. rjparker

    rjparker Senior Member

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    "Car Scanner" app will let you set up gauges to realtime monitor temps and other parameters. This pic is my Prius v engine temp, rpm and speed. You could substitute one or more with inverter temps, of which there are several. Importantly you can read codes to be more specific. Other free apps like Dr Prius will give you codes. I would also verify your radiator fan operation. Fans are not needed when you are moving well so they are a possibility.
    C196E6E1-B68D-4E9A-A459-12E4BBCDFD4B.jpeg
     
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  9. TechnicalGeek

    TechnicalGeek New Member

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    UPDATE:

    So I checked the level of the engine coolant after work and it was indeed lower. I ran the scanner app again and it came back with a code of P148F
    Online research says this is "Engine Coolant pump over revolution"

    Searching that code on this very site says that it needs to be replaced ASAP. I need to beg borrow or steal to get this thing fixed :(

    I limped it all the way home after work after re-filling the coolant and the temps never got above 92 C I did turn the heat on full blast and it was very hot, leading me to believe that the heating still works, it still is pulling heat from the block or wherever it pulls it from. Hopefully its just a pump I do not have the $ for anything else :(
     
  10. Mendel Leisk

    Mendel Leisk Sunday driver DIY’r

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    Yes.
     
  11. jerrymildred

    jerrymildred Senior Member

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    There is no flushing involved. I would just drain and replace. Maybe, to be cautious, drain, fill but don't bleed, drain again, and then fill and bleed. I don't imagine that you added a whole lot of the wrong stuff, so you'd hit the principle of diminishing returns by that point.

    Could be fan, could be pump, could be lot level. The level is easy to check. The others take some more investigation. Using an app with gauges like @rjparker mentioned will help you sort it out.
     
  12. TechnicalGeek

    TechnicalGeek New Member

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    I took it to the (Steal)er today and they hooked it up to their Toyota diagnostic equipment and verified the coolant pump - Replacing it on Tuesday - because they don't have the part.
     
  13. Peter123

    Peter123 Active Member

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    Failing water pumps do not leak on this car. There is no waterproof bearing. The impeller is driven by a spinning magnet. Failures occur when debris jams the magnet. It is usually a cascading failure as some initial debris causes the plastic cover on the magnet to tear.
     
  14. rjparker

    rjparker Senior Member

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    Even normal belt driven water pumps with bearing seals may fail without leaking. That started happening in the eighties with improved seal designs. I remember a Thunderbird that overheated because the impeller corroded away but had zero leaks. So the water pump was the last thing changed.
     
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