Low oil horror story

I'm surprised you didn't get a low oil light come on. Yes I believe there is damage to your engine already, the oil burning will increase from this point. I would suggest you monitor the oil every 500 miles to get a good idea how much oil is being burned.

Who was asking the questions and who was answering?

 

At 172,000 the engine was probably "loose" enough that no additional damage was done. And most likely it was only the last 1000 miles or so that it was really that low. Old engines use/lose oil. Look for leaks; spots on the driveway. It most likely is a combination of rings and valve guide seals and maybe some leaks small enough that they aren't dripping. And check the oil level every 500 miles or so until your next change. Every day would be even better. Did neither of you check the oil during that 7,000 mile interval ?

 

I left a fill cap off once (not this Prius). It was off for a week or two, didn't lose much oil.

It raised a holy stink though, I'm really sorry I put my wife through that, she was mostly driving.

 

To be honest if you never check the oil this is always gonna happen eventually, never a question of if, only a question of when. It might well consume oil at an increased rate after this, so watch it closely.

 

Well things work just fine, right up to the point that they stop working fine. You don't always know when that point is if you don't check it once in a while.

 

It's
Scenario #4.

During the Prius' 172,000 mile service life (so far) the oil has only been checked about 20 times, and even then it was at the wrong time.
Probably even less than that if it's been serviced at the dealership.

Think about it.
How many people check the oil lever BEFORE an oil change?

The Prius is using oil not because of any one catastrophic event but from about twenty, 7-8,000 mile cycles where the oil volume was low, but not low enough to trip the 'change-owner' light.
Whoever changed the oil did so without determining how much oil was left in the crankcase (until this last time) and they assiduously checked the oil level when it was almost guaranteed to be sufficient............right after the oil change!

If your oil burn rate really was (is) less than 1q/5,000 miles then I wouldn't worry about it.
If there really was only one quart in the motor, then I would think that the idiot light would have illuminated or at least flickered during a turn, unless you commute to work at the Bonneville Salt Flats.

Check your oil.
Really.
Like......every time you get gas.
Monitor your burn rate.
Change it at 5,000 miles, and make sure that you (accurately) determine how much was in the motor BEFORE the oil change.

Repeat those steps and drive contentedly, unless your burn rate exceeds a level that you're comfortable with, or the county wants to rent your Prius for mosquito control.
Don't get goofy with additives as a means of telling your car that your sorry.
It's a car. It doesn't give a rip.

You're probably good for another 170,000 miles if you keep this up.

Good Luck!

 

Don't feel bad.
I've been a twidget (Electronics Tech) all of my adult life, and I've got 15 years working with Big Bell.

I bought a new wall phone once upon a time (back when when people had those) because the ringer went out in the old one.

Yup.
You guessed it.
The mute switch had been toggled.

Sounds like your car will be fine.
If you're confident that it had a 1q/5,000 mile oil consumption rate before this last service, then I would call this a statistical outlier and plan on celebrating 250,000 miles with this car.

Good Luck!

Oh yeah.
Don't worry about oil cap either.
I place all of mine religiously on one of the rubber bumpers that the hood rests on when replacing my oil......

.....because I did the same thing once too a long time ago.

 

I would consider adding a half a can of Liqui Moly MOS2 molybdenum disulfide to the oil.

While a lot of other PriusCat members poo-poo it, I consider it to be cheap and good insurance as it leaves lubricant on the cylinder walls and rings and reduces wear in oil starved situations.

Without lubrication from oil or by any other means, wear is quick and irreversible.

However, I'd forget the claims of others about extra mileage.

 

This is odd, as there are definitely numerous reports of people in the same low oil situation, who see the word "Problem" pop up on the MFD and wonder what that is about. It happens usually when going around turns or accelerating quickly, which due to the low level exposes the oil suction pipe for a second and the oil pressure drops. So if the OP's wife is completely ignoring that display, then the message could be missed. I think many people expect that the car will take care of everything, and something so last century as checking the oil can be forgotten.

But I also think the software should be able to note that several low pressure events occur in a set period, and keep that "Problem" up on the screen where it can't be missed.

 

Almost every oil additive ever marketed claims to "cling" to metal parts better than the stock oil formulation.
Independent testing over the years has shown that almost none of them do......and for the ones that do at all, the difference is not significant.

And at 175,000 miles, it is unlikely that there is much friction left to worry about.

I got no problem with a little extra added moly but I don't think a high mileage engine is a good place to start using it.

 

It has nothing to do with "clinging to metal." That is a phrase concocted by advertisers.

It has to do with the striations honed into the engine cylinders and rings at the time of the original build.

Conventional wisdom would lead the individual to believe that a highly polished cylinder bore and rings would make for better sealing of the engine.

That conventional wisdom is wrong.

An engine that "burns oil" is one with ultra high polished cylinder walls and piston rings.

The micro channels or "striae" are the cavities that retain lubricants like oil to seal the gap between the rings and the cylinder walls.

Molybdenum disulfide or MOS2 is a very well known and proven dry lubricant that is known to be less likely to be "washed" out of the cavities than oil, especially by gasoline and ethanol. Ethanol is a cleaner and a solvent that washes out oil.

It doesn't take much metal to metal contact for microseconds of duration to "polish" out the cylinder walls a piston rings.

Once the striae are gone, the only remedy is to disassemble the engine, rehoning the cylinder walls and replacing the rings.

MOS2 is an additive component of nearly ALL oils. Adding little more at very low cost helps but will never hurt the engine.

 

Our 2010 Honda Accord would "eat" oil--- on occasion. From when it was brand new, it ate a quart in its first 4000 miles. I took it to the dealer and asked what to put in it as it was a special break in fluid, and they had never heard of a new engine needing any oil added before the recommended 7500 mile first oil change. They had to call for more info. That Honda would be fine for 4-5000 miles some times, and others, it would eat a quart in under 3000 miles. Very weird car, as it did not have this unusual oil consumption, all the time! We sold it when I had forgotten to check the oil, and my wife told me "it is making a grinding noise"! Sure enough, go around a corner, grinding noise, checked oil, was NONE on the dip stick! It took 3 quarts to get it up, so it was running with one quart in it. We sold it out of fear of long term effects. It was almost 3 years old, with 33K miles on it... Last Honda I owned, as the weird oil consumption was not its only problem... Bought the New Dodge Dart, and it got worse....

 

When the engine cylinders are initially "honed," the striae have sharp edges that are rubbed off during the initial "break in period." This leaves the cavities o tee striae.

That's why I believe in changing the oil after the first 3,000 miles in a new engine.

Another thing I install on a new car is a magnetic oil drain plug which catches the fine iron particles worn off the sharp edges of the striae.

After that, a magnetic drain plug is helpful but not as important.

 

I wonder if this is why engines seem to burn more oil now, the dealers are doing first oil changes after 7500 miles. Before when the industry was doing 3000 mile changes, we didn't hear about oil burning issues as much

SM-N900P ?

 

That sounds like it would qualify as a lemon!

 

I believe that the longer burn time is a component of the increased reports of consumption, but the overarching element is probably still neglect.

Engines are lasting a little bit longer than they did back in the dark ages where 3k oil changes were advocated by fathers and mechanics across the land. Way back then if you had a 175,000 mile motor that was burning oil, the mechanic would look at you and go "Wow! that motor sure did last a looooong time!!"
All three of my vehicles only have a 100,000 mile warranty, and IIRC the folks at Aichi, Japan only need to get 60K out of the motor....so clearly a 10K change interval is "good enough" for the industry.
Furthermore if an owner monitors and maintains their oil volume, I personally think that you have a shot at getting lunar mileage out of a motor.

The problem with a 10K change interval isn't the fact that the oil doesn't retain its lubrication properties out to 10K, but rather the fact that there's not the full 3.9q of oil available to do all of the work that the oil is being asked to do.'

Where does the low oil light illuminate?
3Q?
2.5?
It's the 5,000-7,000 miles that's being put on the diminished oil volume, I believe, that's resulting in increased wear.

 

Until recently, the cylinder honing process was done mostly by hand.

The consistency and "striae" can now be measured with lasers and other devices that can "see" and verify the condition and specifications of the striae.

That's many be one of the reasons they extended the initial oil change interval.

For me, I will always change e oil in a new engine at 3K, leaving the longer interval for subsequent changes.