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2010 burning oil badly at highway speeds

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by lucaspiller, Jun 23, 2024 at 1:19 AM.

  1. lucaspiller

    lucaspiller Junior Member

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    I just went on a small road trip around Europe in my 2010 that's got 260,000km on the clock. For a family of 3 the Prius is really a great car for this. Averaged 5l/100km and has enough space to comfortably fit all the stuff for the trip.

    For a few years the oil has been very dirty (smells like petrol, looks like a diesel engine). I change it every 10,000km with 0W-20 or 5W-30. A couple of years ago I changed the spark plugs and PCV valve, but it didn't have any effect. Last year on a similar trip, on the way back 80km from home, we got a low oil warning.

    I figured it has been burning oil for a while but we just never noticed it before, as usually we only drive around the city. Before starting this trip we have done around 5000km since the last change, and the oil was just below the low mark on the dip stick. I added 500ml which brought it back up to the middle and then went on the trip.

    For the first part we were driving rather aggressively. I'd say averaging 160km/h+ on highways (at one point we followed a BMW X-series at 190km/h for a few minutes - the top speed of the Prius - on the Autobahn). After 2000km I checked, and the oil was lower than when we started. I added 1 litre of oil which brought it back to the same level, and we continued.

    On the way home we had an issue with the rear disc / calliper rubbing and heating so took it a lot slower (average 100km/h) and the oil level is unchanged over 900km more.

    So what I'd like to figure out is what needs to be changed to fix it? I can do a lot of the work myself, and know a place that specialises in engines with a metal shop for anything more complicated. I'd like to understand what needs to be done to fix it properly as opposed to adding "high mileage" oil or anything like that.

    It seems that piston rings and valve stems are the main thing to check. Is there anything else I should look out for? I've read a few comments saying the issues are most apparent in the early Gen 3 models. Was it something that was fixed in a later year? In that case would it be worth trying to replace the engine with a newer one? (I can do it myself, so the only cost would be parts)
     
    #1 lucaspiller, Jun 23, 2024 at 1:19 AM
    Last edited: Jun 23, 2024 at 1:26 AM
  2. Mendel Leisk

    Mendel Leisk Senior Member

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    That’s around 160k miles, for USA readers.
    FYI: the two marks on the dipstick represent (roughly) 1.5 liters.
    the main change is the piston and rings were revised, at some VIN partway through 2014 model year, apparently with the aim of deducing oil consumption. @ChapmanF has more info on the piston/ring change VIN, hopefully will chime in.

    swapping in a later VIN engine is a possibility, hopefully one with lower miles, but I suspect they’d be hard to find, pricey, and may have “other issues”.

    Alternatives:

    1. replace pistons/rings with updated versions.

    2. replace “short block” with new; it’ll have revised pistons/rings.

    3. Swap in a rebuilt engine.

    4. swap in a low miles Gen 4 engine. This was an exciting option a few years back, but had proven problematic, mainly overheating issues, possibly something incompatible.


    waiting in the wings is head gasket failure, which tends to manifest just around your mileage. Reading between the lines, you’ve not heard of this? My opinion, shared by a few others: the head gasket failures are due to carbon clogging of Toyotas newly implemented EGR (Exhaust Gas Recirculation) system. Preventative measure is to clean the entire system, including EGR passages in intake manifold periodically, say every 80k kms. Head gasket failure usually starts with coolant leaking into cylinder one, manifests as cold-start shaking, due to coolant accumulation overnight.

    more info in my signature; on a phone turn it landscape to see signatures.
     
    #2 Mendel Leisk, Jun 23, 2024 at 7:59 AM
    Last edited: Jun 23, 2024 at 8:30 AM
    bisco likes this.
  3. ASRDogman

    ASRDogman Senior Member

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    The oil rings stick, thus the oil burning. Drive FAST, burn more oil.
    The only REAL way to fix it is to replace the pistons and rings with the lastest ones.
    But, you need to check the cylinder walls because they might be oval.
    Short block is probably the better way to go, depending on the cost of replacing
    the short block verses the whole enine with either new or remanufactured.

     
    #3 ASRDogman, Jun 23, 2024 at 9:03 AM
  4. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
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    Touring
    Editorial:

    the main change is the piston and rings were revised, at some VIN partway through 2014 model year, apparently with the aim of reducing oil consumption.@rjparker has more info on the piston/ring change VIN, hopefully will chime in.
     
    #4 Mendel Leisk, Jun 24, 2024 at 8:08 PM
  5. rjparker

    rjparker Tu Humilde Sirviente

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    A 2010 has no chance of having the revised pistons and rings, only 2014 and newer based on the factory and their production change sequence number.

    These are US vin numbers - they may not apply to European models.
    Prius 2014 Vin Production Change.jpeg

    I agree with the comments above, your rings are stuck and there is a very high chance a cylinder wall is scored. These blocks can’t be fixed if they are scored and realistically the best way to solve it for another 200,000 km is to replace the engine. A quality borescope inspection might verify the cylinder walls.

    Borescope technique looking for a head gasket on a v6


    You might find a recent low mile Prius+ engine in Europe as they sold that gen3 through 2020.

    2023 Report
    IMG_5492.jpeg
    IMG_5494.jpeg
     
    #5 rjparker, Jun 24, 2024 at 8:47 PM
  6. bbrages

    bbrages Junior Member

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    Try a piston soak -- google for more info.

    Here is a Toyota cleaner you could soak with: Top Engine Cleaner
     
    #6 bbrages, Jun 27, 2024 at 3:29 PM
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