Which oil do I switch to if I am burning 1 quart/5k miles (2010) Prius

Try 5W30 first, see what it does?

One quart per 5000 miles is not terrible btw, I'd call that light/moderate.

This is getting monotonous, but have you ever checked the EGR, intake manifold?

 

Try using an oil stabilizer and some engine cleaner. I used Seafoam and Lucas Oil Stabilizer and it's been incredible. Still burning more than I'd like. Quite a bit more than you, but that'll help for sure. Then as Mendel said, check the EGR and intake manifold. Keep in mind that'll slow down the problem, not eliminate it. I still do use 0W-20 though.

Seafoam alone slowed down burning by about 50%. Not much considering I burned a quart 10 times faster than you at 1 quart every 500 miles. I've yet to calculate how well the oil stabilizer has worked.

 

1. Install Toyota Prius Oil Catch to reduce oil being sucked into Intake Manifold. Low cost <$50
2. Use 5W30 Long Life Oil, as Mendel Leisk suggested. Preferably MobilOne and MobilOne Oil FIlter certified to 20Kmiles.
3. Perform 1 week piston soak to reduce/elimate carbon build up on piston rings.
4. If number 3 is not possible, run engine cleaner continuosly until oil consumption is reduced. (Seafoam, Techron)

 

Interesting notes from ProjectFarm channel on youtube pit Seafoam against, MMO. Visually MMO cleaned the cylinder better than Seafoam, but Seafoam increased Hot and Cold Compression by 5% and ~10% respectively. Since compression is related to how much your piston rings are sealing against the cylinder casing your best in my opinion is therefore to purchase Seafoam in Bulk from Amazon, or other E-retailer and run at least 5 cans through your engine.

 

How are you "running it through your engine", via small amount in gas tank, some added to oil in sump, or piston soak? Or all of those?

 

Changing to a different oil won't make much of a difference at this stage... But do some research on piston soak techniques and decide on the methods that makes the most sense to you and you'll probably be able to lessen the severity of the oil burning for a little while.

 

I don't have much of an oil consumption issue to speak of, but I am currently 2500 miles into an OCI with an engine oil which advertises to be specifically formulated to help reduce oil consumption related to piston deposits.

valvoline premium blue restore

"Can potentially reduce lubricating oil consumption rates on engines outside of the warranty or extended coverage period by removing carbon deposits from pistons, piston ring lands and other engine components. The dissolved carbon enables the first and second piston rings to move freely restoring oil control."

it appears that Cummins ISX engines are having quite the problems with oil consumption which they've determined to be at least partially related to carbon buildup on pistons and rings and this oil is the prescribed fix, er, well the fix you try before a teardown/re-ring job.

Sounds similar enough to what we've seen anecdotally on the 2zr-fxe, particularly coupled with the numerous examples of carbon fouling in the EGR circuit.

Once I finish the prescribed 5k mile interval with this oil, I'm going to do the full IM/EGR/EGRCooler cleaning and then switch to an ACEA C1 rated oil for the low SAPS. I have a theory that along with moving the EGR draw port to post-catalyst in the Gen 4's, Toyota should also be or have been speccing 'cleaner' oils more inline with the ACEA C series because the EGR cooler is acting like an exhaust aftertreatment device, not unlike a DPF or GPF in our case.

 

Not every Prius develops the dreaded "clogged piston rings".......and not even every one of the vintage that is more susceptible to the problem.

At his mileage, and low oil usage, his might just be due to normal wear.

I would recommend he first change to a "high mileage" oil......and not worry if it is a 15W40 or similar.
Another option is to start changing it about 5K miles when it is a quart low.

I would NEVER put any solvent into my oil.....for any reason. If you are that desperate, maybe you should look for a different car.
Solvents can contribute to seal damage, accelerated bearing wear and oil passages clogging up with loosened sludge.
The fact that some people report good results does NOT automatically make it a good thing to do.

 

When I look at the gunk that comes out of my oil catch can (on the PCV line), I can't see it being good, dumping that into the combustion chamber.

 

I wonder if a "high mileage" oil, for cars with over 75,000 miles, would make a difference? Do these oils have a special additive package for controlling oil burning in high mileage engines?

 

You can verify the instructions on the bottle, but ideally just pouring the entire bottle into the gas tank. And this is if you cannot do the piston soak, "requires you to remove the spark plug".

Personally at the rate of your oil consumption I would just run two full bottles of seafoam in the gas tank, for two gas tanks, considering the size of a full tank of gas. And then maybe 1 bottle per fill up, after you notice significant decrease in oil consumption.
Also consider MMO. Seems to visually clean better than seafoam so that could help in terms of other aspects, but not direcly related to cleaning the piston rings.

From the seafoam website: FAQ/Ask Jim | Sea Foam Sales Company

 

The piston rings need to get cleaned. Simple. The main components oil manufacturer would tweak for high mileage engines are:

1. better detergents
2. lubricity enhancers

Very unlikely that either of these will help to removed the burned and baked in carbon deposits on the piston ring to help it seal better in the engine. Therefore your best bet is to remove that deposit and then run some nice quality oil through the engine afterwards.

For example Mobile 1 Annual Protection is good for 20K along with 20K long life oil filter.





Mobil 1™ Advanced Fuel Economy | Mobil™ Motor Oils

 

On our recently sold 2010, it was consuming a similar amount of oil at 120k miles.

I used BG Products EPR to flush the carbon deposits out with the old oil and BG Products MOA which helped keep the oil basic for the 10k Mile oil change interval.

I also clubbed up to 5w-30 then ultimately 0w-40 and kept the consumption stable at a quart every 5k miles.

Good luck and keep us posted .

 

So, then the question is, are these "high mileage" oils safe for engines with only, say, 20,000 miles? Is it that for younger engines, you don't really need the enhanced additive package, like, for example, buying higher octane gasoline than is required for the engine? In other words, you're spending extra $ for something you don't really need?

 

Ah....the famous "Black Box" argument!
If an airliner's black box usually survives a crash, then why don't they make the WHOLE airplane out of the same stuff?
The answer, of course, is that an airplane built like a black box wouldn't work as an airplane.

Short Answer:
It's not like Geritol. Using high mileage oil when you so not have to might actually cause slightly increased wear in things like valve guides and gaskets.
https://www.cars.com/articles/is-oil-for-high-mileage-engines-worth-the-extra-cost-1420680439321/

Longer Answer:
Engines burn or leak oil from a variety of reasons ranging from abuse, neglect, prior crash damage, or a combination of several of those things, but MOSTLY from the most powerful force in the universe: Time.
The great philosopher Robert "Rocky" Balboa once said: "Time, you know, takes everybody out. It's undefeated."
I think that they named a park after him out west.....

So....
Most properly maintained engines start using a little oil as valve guide seals get less sealy though a combination of wear and age. Age also causes all of the other gaskets in the engine to become a little more brittle and sometimes this will result in a little leakage here and there.
While all of this is going on, drivers who do not properly maintain their cars like it says in the manual will not be checking their oil level, and so a smaller, dirtier amount of oil will be forced to do the same amount of work...less and less effectively.
This sometimes results in increased bottom end wear (rings, bearings, etc....) and MORE oil burning.

Not as big a deal in a 5.3 liter truck with a 6-quart sump and slightly thicker oil.
A little more so in an eensy-weensie 2-liter with only 3.something quarts and a 10,000 mile oil change interval.

The only thing that is guaranteed to stop excessive oil use is about 100 retroactive oil checks and top-offs - and since Musk hasn't invented a time machine, that's not an option yet.

Besides....
AFTER he invents this device, runs a few cats through it before certifying it for human use, and goes back and buys enough bitcoin to rescue Tesla and "take back" some tweets.....we'll be complaining about excessive battery drainage in our BEVs instead of oil burn rate for our cars.

Until then?
Age happens.
It manifests itself in humans with the 100s of 'male enhancement' commercials and 'Depends" ads that Boomers are increasingly pretending not to be interested in.....and with cars, it's associated with a little oil use between changes.

 

What I've read: oils marked "high mileage" have ingredients that swell the valve seals.

My hunch, coupled with some reading: I wouldn't use them unless you know you're losing copious oil through the seals, as a last-ditch, k-seal sorta thing, and once you start using it, stick with it, since returning to a regular oil the seals tend to shrink back, and end up leaking more than at the outset.

 

This is my understanding as well, I will not switch to an HM formulation until I have some serious leakage occurring despite being well above the 75,000 miles or whatever their marketing figure is.

 

If you read the info on the bottles, they really underplay this. It's more like "Over 75K miles, this is the oil for you". I can recall almost falling for this.