Burning oil

You probably need to consider moving up in oil weight to reduce your consumption. These cars are known to consume oil. Good for you for keeping an eye on things. Others find out after the damage has been done.

 

Curious, moving up in weight to something like 5W-40 to 10W-30?

 

Royal Purple is great oil, but a little pricey to be feeding an oil burner in my opinion. I agree with the others that a heavier oil should reduce consumption, but at the cost of a little worse fuel economy.

Just for comparison, my wife's '07 with 124,000+ miles burns about one pint every 5,000 miles using Toyota 0W-20 oil. I change the oil every 5,000 miles.

 

Move up to 10-40 weight.

 

Just had my 3rd oil change done today with Mobil 1 oil 0W-40 oil. Car has no ill effects and gets in the 50's mpg.

 

Just keep in mind that:

the xxW portion of the designation is how much it thickens under cold conditions. IE 10W thickens more then 5W.
the second set of numbers is the oils resistance to thinning under high temperatures IE -40 thins less than -30

So... a 0W-40 compared to a 5W-30 thickens less in cold condtions and thins less under hot conditions

 

0W-40 oil is ideal for North America climate, cold mornings and warm days, especially in the west.

 

the engineers that design and build engines make the oil delivery system efficient for the lubrication of the engine and also for return oil flow and cooling of oil. oil pressure is what keeps the rotating parts away from each other and oil pressure is measured thru resistance. viscosity and wear effect oil pressure. in the Prius, too thick of oil will not reach bearings in a sufficient amount of time to deter wear, hence the use of thinner oil as the engine starts and stops many times during a trip. the anti-drain back valve on the oil filter gets a lot of use as it keeps the oil in the galleys when the engine shuts off. using a thicker oil other than what the OEM calls for in that year of vehicle is putting a Band-Aid on a different problem I.E. worn valve guides or stuck piston rings. burning less oil between oil changes isn't necessarily a good thing. VVT (variable valve timing) is mostly run by oil pressure. VVT lets an engine advance and retard timing thruout the rpm range to maximize power, torque and even gas mileage.

 

The 2007 manual calls for 5W-30.

I read here long ago that they have revised the recommendation to 0W-20 and that's what the Toyota parts guy always thinks I want. Like I said, I used 0w-20 up till the last change. I'll see if it makes any difference in burn rate or gas mileage. BTW, the Toyota synthetic oil is made by the same people who make Mobile1. But you can't get it in 5W-30 in the Toyota brand although you can get it with the Mobile1 label.

@TMR-JWAP makes a great point on the implications of the numbers. I've never done a survey, but I'm pretty sure that the wider the spread between the cold and hot numbers, the more expensive the oil.

 

And a "high mileage" formula.

But that seems like a LOT for a car of that age and mileage.
Probably should do a good inspection for leaks.
And service the PCV system if not done recently.

 

Bull. If you are going to make outrageous statements like that, you need to provide some evidence or technical reference.

For that to actually happen, you would need to be using something about the consistency of thin grease.

 

I think you need to open up a Europen or Australia Prius manual and look what the Prius in the rest of the world is allowed to run in the Prius motor. The only reason we get 0W-20 weight is so that it meets CAFE standards. You don't see oil burning complaints in Europe.

 

I'm not in Europe, I'm in the USA, replying to a forum post on burning oil. My 08' base model uses oil and I've read tons of post on this issue, even tried the techron for several tanks of gas. we got the car new and until about 100k I used RP oil and spun on a new filter every 5k or so for 15k then changed the oil. I drive this thing from 50 to 100 miles a day and still get 48.x gas mileage. now I use Castrol high mileage 5w-20 for 5k. our 15' with the 1.8 has mobil 1 in it and it gets a new filter every 5k until 10k then it gets new oil. the ppl that do the techron and get good results is because the techron removes carbon build up that may or may not cause sticky rings. without a complete teardown no one really knows, just that their oil consumption goes down. Mr Spade 2, it is not bull, it is fluid dynamics. suck water thru a straw then try sucking molasses with the same straw, its tougher because molasses is more viscus that water. most engines that run constantly have an oil pump that sends oil thru the engine at a constant basis. the prius engine is the same only it doesn't run constant. thus it needs precise oil delivery that is reliable. not trying to solve the worlds problems, just stating IMHO that using a different weight oil than what the OEM specifies is not helping the cause of the oil consumption.

 

You are welcome to your own opinion but are not welcome to state an opinion as though it was fact.

There is nothing anywhere near to "precise" about oil delivery in a combustion engine. Excess oil slops all over everything, pretty much. Except for the thin film that is between the rings and cylinders, that is. When that space becomes wider, a slightly thicker oil sometimes helps with consumption......and hurts exactly NOTHING.......as long as you don't use grease.

 

me too. Really helped the very minor oil loss.

 

You miss understood me. Toyota for Europe and Australia state to use 30, 40 and even 50 weight oil in the same engine we have. So if Toyota is recommending thicker weight oil for other parts of the world, then you would have to assume OW-20 is only being used to meet CAFE standards.

 

To OP: I would try a 5W-40 or 10W-40 oil. If you look in the user manual, 10W-40 is listed as okay down to something like -20C. So unless you'll be starting the car in extremely cold temperatures before the next oil change, it will be fine. The Prius engine is a consumer engine and is therefore designed to perform acceptably under a wide range of oil viscosity/pressures.

Two additional things to consider:
1. Run a few tanks of fuel injector cleaner (Techron or other with PET). The most common cause of oil burning in our engines is worn and/or gunked up piston rings. The cleaner certainly can't undo any wear, but it can clean up some of the gunk. Some report oil use dropping after fuel system/injector cleaner.
2. Install an oil catch can. The worn/gunked up piston rings burn more oil as they allow more blowby gasses into the crankcase, which then pushes the oil vapor into in the intake via the PCV. An oil catch can will catch this oil instead of allowing it to burn.

You don't want to burn oil in the engine, as the burnt oil will clog up and damage your catalytic converter. It's not too rare for Prii to end up in the junkyard because oil use increases to a point where it's a quart every couple hundred miles and the cat is bad. At this point the car needs a new engine, cat, and if the hybrid battery likely only has a few years life left, it's not worth it for the owner to fix.

 

Mr. Spade 2, you are incorrect on both accounts. It is not my opinion that the oil delivery system in any combustion engine is in fact precise, this is a true statement. you say excess oil slops everywhere, that is true. the precise part comes in when the oil is under pressure to the rotating bearing surfaces... I.E. cam, crank and rod. I did a quick search to see if the connecting rods of the 1.5 engine had spit holes or not, those lubricate the cylinder walls, the pics I found were absent of said spit holes so the "slopping" of excess oil must lubricate the cylinder walls, however I did find that there is a cutout that may allow oil to squirt out onto the cylinder walls. piston rings by design are engineered to expand with wear to keep in tight contact or seat with the cylinder wall. there are 2 compression rings and 2 oil management rings separated with a spacer. the compression rings are/should be gapped at .0010 and this will change with time but not much at all. carbon build up keeps the rings from seating against the cylinder wall and allows blowby into the crankcase and unmanaged oil that is burned in combustion into the crankcase and exhaust, straight to the cats hence the reason to use a fuel additive that removes said carbon build up and frees the rings to again seat against the cylinder walls. oil doesn't just magically appear in the combustion cylinder, it is introduced via worn valve guides/seals,faulty pcv valve or stuck rings. Mr. Denver, you are absolutely right, you cannot reverse the wear on any engine. if you need an oil separator then its probably to late unless your FI (forced induction).