Prius question - erratically "losing" oil - car buffs please help

[happy]

I have a 2009 Prius, i tech, 3rd gen, with 150km on the clock.  I have it serviced every 10k km by  a  toyota dealership.

All of a sudden at around 127500km the yellow triangle of doom started flashing going round corners on hilly terrain. After a week or more of this it stayed on long enough for me to read the error message was low engine oil. Yikes! I was down a hair pin gorge, on the way to a very important meeting in the middle of nowhere.  I hit the nearest general store some maybe 5-8km up the road, checked the oil - EMPTY and in my haste bought and poured in 3litres ( approx 3 US quarts of oil).  Later that night, I couldn't figure this out...engine not leaking oil, no oil in the coolant, and no exhaust smoke...WTF. The dealership was not reliable in doing minor things they said they did, like filling the windscreen water, so I figured they'd not filled up the oil properly.

The next 10k, all is ok...no lights. I was remiss I didn't check the oil level myself, since there were no problems and I had convinced myself the dealership were dufus'.

Now 147500.... a couple of flashes of the yellow triangle of doom. Quick check, just about no oil. Put in a litre. 700-1000km later a couple more flashes...another litre. More research. Discovered I really should check the oil before it hits the yellow triangle of doom.  So another  litre later, I am finally at the low level pip on the oilstick. Feeling a little foolish I didn't monitor the oil more closely after the first incident. More research. Discover that the oil replace volume for a completely dry drain in my car is 4.1l.  WTF, I've just put 3l in to get to the low pip. More research I discover that  my car should use max 1 litre/1600km. The math doesn't add up. Car still running sweet with no increase in petrol consumption or visible signs of oil loss.

Questions:
1. Can anyone shed any light on whats going on?
2. Did I blow a PCV or other seal/valve? ( its doesn't seem to be the rings at this point)
3. Is it likely to be expensive?
4. Is it a sign that the car was abused before I bought it? I bought it at 89k km. It was regularly serviced up to 60k,  the the dealership alleged they had had it between 60 - 89km...but no service record available for that period, so that could have been a porky.  If so should I get rid of it before it causes me more engine trouble?   I had hope to run  up  >250km or longer if it was holding up OK.

Sorry re long post, if you are still reading and can help, thanks in advance.

[sokoloff]

The space between the top and bottom marks on the dipstick is usually 1 qt/ltr. So, if you get a handle on what the normal/steady consumption of oil is, you can just add a quart now and again on a progressive oil change schedule. (Still do a full change at some point, to get the old filter out of there, but you'll be secure in knowing your car's oil is never all that old... :) )

The oil is going somewhere. It's either being burned or leaking. First step is figuring out which. Given that you haven't described your engine as an oily mess and haven't spun in your own oil yet, it's probably being burned. And except for the possibility to plug the catalytic convertor, there's not that much wrong with burning a little oil, so long as you keep the engine with sufficient oil inside. You might be burning that amount without visible smoke, but I suspect you might be able to see some smoke on cold startup first thing in the morning.

In terms of your car being a lemon, mechanical things break. If this is the first major thing to wrong, you're doing OK. Now, since there are no signs of problems, you can probably sell the car for decent coin now and upgrade to a somewhat newer used car. That might be the money-ahead plan, and you need to make your own peace with the ethics of selling a car without disclosing why. The other alternatives are to chase the source of the oil burning or to drive the car as-is.

If the oil consumption is stable and you drive it another 100K at 1K/liter, you're looking at buying 100 liters of "extra" oil. That's not that much, so as long as you're OK with the possibility of forgetting to manage the oil properly and causing damage/getting stranded, with the possibility of plugging the catalytic convertor, and with the certainty that you're polluting more than if the car was running in top shape (though still perhaps less than euthanizing a working car and replacing it with another).

[Ecky]

Prius engines almost never fail and as such, are extremely cheap. Chances are good you can get a newer, lower mileage engine that doesn't burn oil dropped in for relatively cheap. Probably not as cheap as just adding oil, mind you, but there are other benefits.

[Another Reader]

My neighbor has a similar problem. Can't remember if the car is 2009 or 2010.  Apparently there is a known issue.  You should probably check the Prius forums to see if this is discussed.

I don't think he was happy with Toyota's response....

[happy]

The space between the top and bottom marks on the dipstick is usually 1 qt/ltr. So, if you get a handle on what the normal/steady consumption of oil is, you can just add a quart now and again on a progressive oil change schedule.

Thank you - this is useful.  I will start monitoring every 1000km and see if I can work out the best interval to add another quart.[

quote author=sokoloff link=topic=64016.msg1293219#msg1293219 date=1478434014]
The oil is going somewhere. It's either being burned or leaking. First step is figuring out which. Given that you haven't described your engine as an oily mess and haven't spun in your own oil yet, it's probably being burned. And except for the possibility to plug the catalytic convertor, there's not that much wrong with burning a little oil, so long as you keep the engine with sufficient oil inside. You might be burning that amount without visible smoke, but I suspect you might be able to see some smoke on cold startup first thing in the morning.
[/quote]
Pretty sure its not leaking - I would be able to see something with this amount of oil loss I'd say.
I'll check more closely for smoke

In terms of your car being a lemon, mechanical things break. If this is the first major thing to wrong, you're doing OK. Now, since there are no signs of problems, you can probably sell the car for decent coin now and upgrade to a somewhat newer used car. That might be the money-ahead plan, and you need to make your own peace with the ethics of selling a car without disclosing why. The other alternatives are to chase the source of the oil burning or to drive the car as-is.

If the oil consumption is stable and you drive it another 100K at 1K/liter, you're looking at buying 100 liters of "extra" oil. That's not that much, so as long as you're OK with the possibility of forgetting to manage the oil properly and causing damage/getting stranded, with the possibility of plugging the catalytic convertor, and with the certainty that you're polluting more than if the car was running in top shape (though still perhaps less than euthanizing a working car and replacing it with another).

Mmmm I'm giving the 2 options ( see or keep adding oil) some thought. Will start looking around.

Prius engines almost never fail and as such, are extremely cheap. Chances are good you can get a newer, lower mileage engine that doesn't burn oil dropped in for relatively cheap. Probably not as cheap as just adding oil, mind you, but there are other benefits.

Interesting thank you. I hadn't thought of that. Will investigate this also.

My neighbor has a similar problem. Can't remember if the car is 2009 or 2010.  Apparently there is a known issue.  You should probably check the Prius forums to see if this is discussed.

I did find a bit but probably didn't search the right questions. I'll have another go thanks

I don't think he was happy with Toyota's response....

Pretty sure I won't be either!