engine oil went dry

The reason you haven't seen anything, because the causes are unknown. Maybe even to Toyota. Now, they are not even interested to know, as those problems don't surface under warranty. In a way, it could be a beneficial thing for them in a form of built-in obsolescence.

I can tell you from studying many other examples of oil consumption in Toyota engines (specifically 1ZZ-FE and 2AZ-FE), that the problem usually is too little oil circulation in oil control ring grove. That combined with too hot pistons results in oil coking permanently closing oil holes in pistons and gumming up the rings.

Whether that's a case in prius engines is only a guess. The only proof would be reversing early cases of oil consumption by doing piston soaks with Kreen. Unfortunately, when most people discover oil consumption, it's too massive and too late to do anything to correct it.

But, like I said in my post above, I'm thinking low tension oil rings are at least in part to blame.

 

Or the oil hole diameters are too small and get plugged up. The Gen 2 Prius piston oil ring assembly is only 2 mm thick as I recall.

 

jadziasman, friendly_jacek: Really good points. One of last attempts to fix the 06 Gen II I had was using AutoRX. I was going on the assumption the oil closing holes were plugged or things were gummed up. I never got to see the end result as I traded the car. If the claims are true as everyone says, I would think AutoRX (with a good oil too) used at certain mileage intervals (e.g. 15,000 - 30,000 - 50,000 etc) may help reduce this issue down the road??? I was hoping to find someone who took the engine apart to investigate (and possibly correct the problem) but I haven't see a post that goes this far. I think a lot of us are either just dealing with the oil consumption by adding or getting other vehicles cause we don't want the hassle factor.

Friendly_jacek, here's a perfect thread about Kreen and the Prius. Problem is we're left hanging- no updates if it worked. Looks promising.

Kreen test... | Oil Additives | Bob Is The Oil Guy

brian

 

High mileage or older engines use more oil. It's been that way since the beginning of time. More likely to happen if people let the oil run too low.

This is nothing new or nothing unusual.

 

Thank you!

 

BMW is famous for burning oil. Many will burn some oil from new. I believe Japanese cars are what made us all accustomed to cars that do not burn oil. Old pre 1980's american cars of almost any make or model burned some oil. Toyota determined that you can never make a perfect piston or cylinder so they measure size beyond regular machining tolerances and classify the cylinder by size (a b or c ) and stamp it on the block. Then a matching a b or c piston is used in that cylinder. This allows tighter tolerances than the engine machine tools can achieve. I don't think other auto makers bother with that system, they just say the engine tolerances are good enough with all identical pistons.
It is a delicate balance that allows an engine to run without burning oil. I am surprised more motors don't have oil consumption issues. Running low on oil once is all it takes to make the engine an oil burner. Once the engine is loose it will never be fixed. Changing your oil every 10k miles is a long interval. I think the oil maintenance reminder comes on gen 3 comes on at 5 k miles.

 

This is the important bit.

Once run low it'll never, ever be the same and will burn more oil. Add this to an owner who allowed the car to run very low and we all now know why they're suffering problems.

Rocket science it ain't.

 

Not normal at all. You need to check the oil after an oil change. Even if the dealer did the oil change. bring the car home and let it sit and then check it. Then start checking it once a week. You should have never let it get that low. And the only way it would get below the stick in 10,000 miles is if you never checked it. Or if you don't have the minute or two to check it, just pay the 3-5 grand for a new motor when it blows up.

 

Do you REALLY expect that every engine ever made will go more than 100K miles and exhibit NO additional oil burning as it ages ??
If so, that is an unrealistic expectation.

Moving engine parts wear. That causes the oil loss to increase as the use piles up.
Some wear more than others; some use more oil with age than others.

This is not a big mystery.
There is no "solution".

 

Thanks for the link. I haven't seen that Bitog thread. One comment, when piston oil holes are blocked, you can't open them again short of drilling hard carbon out. This is why solvents work only early on before holes are blocked. BTW, autorx is too weak to do much.

 

Sorry, but you are wrong. I have a yaris and I can tell you oil consumption is unknown in yaris. There are folks with 500,000 miles on yarisworld and never see any consumption. Yet the same, or almost the same engine in Prius burns oil by 150,000 or earlier.
Similar situation with 1.8 in corolla vs gen3 Prius.
So, the facts are not on your side and you are just speaking as Prius fan boy.

 

RT*M? I know I saw it in the owners manual.

This allowable consumption figure is essentially the same as the figures listed in the owner manuals of all other cars of all brands in my household over the past three decades.

 

Are you sure you quoted the right post to reply to ??
It seems like you are saying exactly that same thing that I was trying to say.
What exactly did I say that is "wrong" ??

 

Nope, please reread my post.

 

I did, several times before replying.
I did again just now.
Except for it being obvious that you are throwing an insult my way, I don't understand
any of it. Honestly.

 

It depends. Did you do the blend of oil, or full synthetic? The 'blend' (1/2 regular / 1/2 synthetic) should be changed every 6 months / 5,000 miles (with a 5,000 'safety buffer' inbetween) and the full blend is 12 months / 10,000 miles. I would check what the dealership last used. If they used the blend, its normal, because the oil has run its course. If they put the synthetic, I would raise a ALOT of questions. Just ask what oil they used. I used to sell Toyota's, that's how I know about the oil.

 

I reread your post again.
When you said "Some wear more than others; some use more oil with age than others." and you meant that Prius used more oil than other toyota cars with similar engines, then we do agree indeed.

I concentrated on the first part "Do you REALLY expect that every engine ever made will go more than 100K miles and exhibit NO additional oil burning as it ages ??" that sounded like marginalizing the problem of oil burning in older prius.

I disagreed with that part. Sorry if insulting, not intended.

​

 

It just cannot be emphasized enough how important it is to check the engine oil a lot more frequently than when it is time to replace the oil.

I take a long trip every two weeks, so I check oil and fluid levels every two weeks. I also check the day after an oil change.

 

At 200,000 kms I am still getting no oil consumption, judging by the dipstick. However I have noticed my oil becomes amber earlier than it used to.