2008 Prius - burning oil at 135,000 miles

If I was going as far as to removing the cylinder head to replace the stem seals I would also be dropping the sump and then replacing piston rings and big end bearings.
The great majority of the work is removing the head. It then becomes difficult to know where to stop, "new valves and guides, timing chain and tensioner" The parts would soon add up to more than a low millage engine, but just replacing the valve seals would give no guarantee of curing the oil use.

John (Britprius)

 

How much oil is the engine consuming at 354K miles?

As long as the engine isn't fouling the catalytic converter or oxygen sensors, you shouldn't contemplate major engine repair at a set odometer reading. Keep driving Ema until this happens or until fuel economy suffers.

 

Ema is burning about a quart every 1,500 miles or so. She is starting to foul O2 sensors and is generating Cat errors, P0420. I reset it with the scangauge and keep going, LOL. If she passes emissions testing in February/March I will keep driving, feeding her oil and replace the O2 sensor.

Then it becomes a debate of new engine, new cat, new suspension parts and possible other issues (battery) against a new Prius. I kind of would like to have Ema make it to the next generation in late 2014 or 2015 if they come out then but only time will tell.

Happy driving,
Chris

 

This engine still has the crosshatch pattern on the cylinder walls!!! This means very little wear.
I would only clean pistons, put new rings in, new seals and put it together.

 

I would like to share my experience under this thread of my 2007 Prius starting to use oil. My experience is the same as drivesalot as far as my engine all of the sudden using oil. I had a brother in law that worked for Toyota and would always take my car with him to work for oil changes. He switched jobs and I lost this convenience!

I then took my Prius to a quick Lube where they talked me into using synthetic oil. It cost more and I love my car so I said yes... Just a few weeks layer my red triangle alerted with the oil symbol and I checked my oil stick and I was over 2 quarts low... I did not know why so I added oil and then took the car to get another oil change. I used synthetic again with the same result. Several weeks later I get the same warning.

I believe the cause to be switching to synthetic oil when my car was conditioned to regular oil.
I have since switched back to non synthetic oil and I will see what happens with the oil level.

One possible problem that resulted from the engine burning the oil is now my check engine light recently came on with a code P0420 error which has to do with the catalytic converter malfunctioning. I read that an engine burning oil can poison the catalytic converter and ruin it !
I can't confirm this problem, but all this I have described has happened in a 3 month span of time.

My car has never burned oil. I have never seen evidence of a leak. The engine must have burned it. Is it possible the synthetic oil did something to the oil rings?

If anyone has a similar situation please post here.

Thanks

Update: My Prius is still using oil after switching back to 5w-30 penzoil motor oil. It has burned about one quart in 1500 miles of mostly highway driving. I reiterate that this car never burned oil until I switched to synthetic for two oil changes and I am convinced this had something to do with this problem. I am thinking about taking it to the dealership and let them have a look but I am fearful of what that is going to cost. I have around 150,000 miles on the engine. Is there anyone else out there that switched from regular motor oil to synthetic and experienced this problem?

Thanks,

 

So what if your car uses 1 quart per 1,500 miles of driving. That will cost you around $3 per quart. Considering your odometer is reading 150K miles, that is not unusual.

It is certainly possible that the switch to synthetic oil prompted an increased amount of oil consumption. Regardless, why would you take any action, knowing that engine repairs will cost you at minimum in the high three-digits and more likely, low four-digits?

 

Hi Westy. One thing that's difficult to untangle in cases like this, is what effect did driving with low/no oil pressure (because that's what the light means) have on the situation. The rapid oil depletion following the quick lube change could have been caused by a number of things, such as the use of poor quality oil and/or an under fill. This shouldn't have caused an ongoing problem if the oil level was noticed earlier and the oil topped off or replaced. The fact that it's now an ongoing issue may mean that the actual cause of the problem was simply due to driving the car with insufficient oil.

BTW. We get a few reports of Prius with high oil usage reported here in these forum, and to be honest they almost all read exactly like yours. That is, in almost every case the first indication of a problem is when the owner notices that they're driving with a low oil pressure warning (engine light). Unfortunately this makes it very hard to know if the high consumption problem was pre-existing, or if the initial low oil was something incidental (one off bad oil or underfill) and the problem actually started *after* the event. As with your case we'll probably never know.

 

Many thanks for posting the pictures of pistons. A question for you. Did you see it they were oil holes in the oil control ring grooves? How many holes per piston? Were they plugged up? The reason I'm asking is most of recent Toyota problems with oil consumption boils down to too few oil holes that tend to plug in and foul oil control rings. That was also a problem in Saturns.

See this picture for location of the holes:

 

Is that bad or good? I've heard both ways.

 

Yes thanks for the reply and you are right about everything you said. I am considering buying some Lucas Oil Stop leak and giving that a try to see if it has a positive effect. Any opinions about trying this?

 

Yes I agree that that high of a repair would not be worth it. I am considering trying Lucas oil stop leak to see if that helps the oil consumption. I have also been holding off buying a new Prius to see what the new design is going to look like, but I heard it may not be out until 2015 :-(

 

Also, my mechanic told me that he tested the old disassembled engine by filling the cylinders full of transmission fluid. All of the fluid leaked out within 2 to 4 hours for each of the cylinders.

According to my mechanic, that is bad. It implies insufficient engine cylinder seal.

 

Chris, that's a lot of labor to do on a hope that it will fix the problem, especially with 350k+.

 

There are 8 drainback holes per piston. They are all very dirty, perhaps not completely plugged up. Did not see any drainback notch.

 

Joe,

If I do anything at this point to Ema it may be an "engine soak" depending on how AllenZ fairs with his from this thread:

Burning oil at same rate regardless of oil thickness --- What does it tell us? | PriusChat

If that doesn't seem to have any decent results I will probably just swap engines if The Burn gets any worse. My issue is I really don't like the Gen III's flying bridge and I really don't like that you can only get DRCC in the Five with 17" wheels. I'm hoping Ema passes emissions and can just be fed a quart every 1,500 miles or so until the next gen comes out.

Happy driving,
Chris

 

Everyone,

I wanted to post an update on Ema's oil burning because ... wait for it ... it has actually shown significant improvement in the last month or so.

She now is burning at only 1 quart every 2,000 miles and sometimes better right after an oil change. What is the difference? The ONLY thing I have done different is a switch to ethanol free gasoline whenever possible and when not possible I add 2 oz. of Lucas Oil Ethanol Fuel Stabilizer at fill up.

That is really the only thing different and not only has it made a difference with the oil burn but my MPG's have gone from 35-40 MPG with ethanol gas to 44-49 MPG with non-ethanol. That is a HUGE jump and right at Ema's lifetime MPG and at her "Summer" MPG numbers the last couple years. Not only are the MPG's better but the engine is NOTICEABLY smoother, quieter, has more power, etc... etc... How do I know? Driving so much I routinely go up numerous hills here in the south and almost always use cruise control. With a scangauge I don't let Ema go above 4,000 since the burn started and there are now hills I can go up with ethanol free gas at under 4,000 RPM that I can't with ethanol gas.

It might be something to try for all of you out there experiencing "The Burn". I would give it at least a tank or two. I downloaded an app called Pure Gas to help me find ethanol free stations.

I am still getting codes for fouled O2 sensors and the occasional Cat code so it will be interesting to see if Ema passes inspection in the next few weeks, lol.

Happy driving,
Chris

 

Everyone,

Ema passed emissions this morning!!!!! WOOT WOOT That means I have another year and 40,000 - 50,000 more miles that I can keep feeding her oil and seeing if anything affects "The Burn", lol.

Actually from my post back in February I have more data on her diminished oil burning when using non-ethanol gas. It is down to as little as 1 quart every 2,000 miles and that is if I push her hard at times over 4,000 RPM. If I keep her below 4,000 RPM on hills I could probably do 3,000 mile OCI's and not have to add any oil at all. She would be down to the lower dimple but is certainly not burning the 1 quart every 1,500 miles she was.

And as I mentioned before the engine sounds SOOOOO much better and smoother on pure gas. The power is better and the MPG is "summer MPG" or maybe better, lol. Ethanol sucks!!!!

Happy driving,
Chris

 

Nice to have the option available of being able to buy non-ethanol gas - up in Michigan, the only place you could get it is at marinas, and the price premium is about $2.00(at least) more per gallon. And to add insult to injury, marinas have been switching over to gasoline with E-10. So pretty soon we wont have any gasoline without ethanol added.

 

But wait, didn't you report 1qt/2000 miles as your baseline consumption back in 2012? Looks you just reverted to your normal after the unfortunate Seafoam experiment. I was never impressed with Seafoam as an oil additive, especially in hard working engine. Furthermore, we don't know if it was E0 or Lucas Oil Ethanol Fuel Stabilizer that made the change.

 

My first post was of that useage or there about yes. Of course that was 60,000 - 70,000 miles ago and for the first 40,000 - 50,000 miles before that when she started burning I didn't keep a real good track of oil consumption. She might have been burning from 200K. It was only when I got down into the area of consistently needing a quart every 1,500 miles that I really started keeping a close close eye on it.

What unfortunate Seafoam experiment? I think the Seafoam works well as a cleaner. The only dramatic increase in my consumption I saw was when using an entire quart of MMO which is expected since it thins the oil so much.

Ummm why add Lucas Oil Ethanol Fuel Stabilizer to fuel that doesn't contain ethanol? And regardless the lack of ethanol and/or its stabilization has decreased Ema's oil consumption.

Happy driving,
Chris