2008 Prius - burning oil at 135,000 miles

I have to add a quart of oil every 800 miles, basically once every two weeks.

Recently replaced spark plugs. All of the old spark plugs indicated potential valve guide seals leak resulting in seepage of oil into the combustion chambers. Do not know how difficult, or expansive, of a job to inspect and/or replace all of the seals.

 

How many miles has it done John? Also, what oil (grade/brand/etc) are you mostly using?

 

I'm wondering what your car's current mpg is, and how that relates to the mpg back at a time when the engine was not burning oil.

 

Patrick,

Believe it or not the MPG's are still pretty good. They actually may be a little bit better than than have been in the past few months. I am still averaging around 46.5 when measured at fillups. They computer thinks I am doing a little better than that at around 48. Those are both around the historical averages for Ema.

As with any MPG calculation there are a thousand things it could be. The wearing of the tires, better gas, tail winds, summer MPG or it could be that the 10W-40 being thick has helped the compression and power more than it has increased friction in the engine ... who knows, LOL.

There hasn't been any wierdness out of the battery <knock on wood> so that seems fine. The next thing to go on Ema will be the Cat. I get occasional p0420 codes on her so the Cat is pretty much used up now as well. Hopefully she will pass inspections in February and I can drive her for 2014 yet but we will see.

I will certainly post more as things happen.

Happy driving,
Chris

 

Sounds great, Chris. Since your car's mpg is still quite good, maybe the oil consumption is more related to leaky valve stem seals (which would not impact engine compression.)

 

Does anyone know what material the valve guide seals are made of? Could this be the culprit of some of the Prii oil burners?

 

My car has approximately 185,000 miles. I always use 5w30. No particular brand affiliation. Just use whatever is on sale.

 

i have 300,000 km (180k miles) and i haven't checked my oil since 7500 km, i will check and report back since i got this problem too! Since I can have the car sit for 24 hrs before checking the stick at a even level. I drive a lot of highway too but I baby my prius as much as I can I cringe when the rpms are above 2500 rpm but I do drive at 120km/hr when I can. Which on my scangauge I try to maintain 2300 rpm to stay at 120km/hr on flats

 

Like others, I suspect that more than a few of these oil burners are valve seal related.

I suspect that the longer intake valve duration of the (pseudo) Atkins cycle and the associated pressure pulse wave created in the intake port is causing early valve stem seal failure.

Just a theory.

 

after 8k on my previous oil change and letting the car sit for an hour I got 60% of my oil left on the dipstick probably 60% highway/40% city if i had to guess. I hypermile when I can

always used on sale synthetic oil 5w30

i got the car 160,000km now it sits at 300,000km every 8000 km losing 40% of your oil is not too shabby! I'll take it!

 

Hi Phil. If you're referring to the oil being at about the 60% point between the low and high dimples on the dipstick, then that is way more than 60% of the actual oil in the sump. This would correspond to only about 0.8 quarts lost over 8000 km, so about one quart per 10000 km. Yep this is perfectly acceptable consumption for the age/miles of your engine. If you want to keep things good, do make sure you still check it regularly and top off as needed.

BTW, I'm pretty similar. At just under 200,000 km I'm using about one quart every 14000 km. I consider this perfectly acceptable too.

 

Dang...Phil uses less oil than I do and I only have 70,000 miles

 

lol yeah i try to baby my car anything above 2600 rpms I start to feel the pain for my engine lol!

its almost been 12k since my last oil change, i considered going for 20k oil changes and doing an analysis since I'm showing concern about its age and never done an analysis to boot!

I will post pictures soon!

 

How do you know what your engine rpm is? Do you have a scangauge or an ultragauge?

One thing I dislike about the gen 2 Prius is the dearth of gauges on the instrument panel or MFD.

Toyota should have included more them but probably decided that most drivers need only two
gauges - fuel level and speedometer - sigh.

 

scangauge II user for around 5 years now, i used to have the canview but broke the wires accidently. I i got to find a crimper tool to fix it but it has been awhile since ive done that. I do miss canview though the scangauge updates slow compared to CANVIEW and it has way more stats to show for it!


they had to keep the prius cheap somehow

 

I think the reason behind no rev counter is because of the Prius engine shut off at lower speeds, and Toyota thinking of all the complaints about the rev counter being intermittent.

John (Britprius)

 

I doubt cost was the reason. Toyota decided the HV battery SOC screen displayed with the INFO button on the MFD was more important apparently.

 

I really hope that the vast majority who have purchased a Gen II Prius would be aware that the gas engine does not run at certain times.

 

I honestly think the reverse is true. Most members on PC will know this, but PC only has a tiny minority of Prius drivers as members. PC'ers are generally also technical people, the same cannot be said for the rest of the motoring public.
Most Prius owner put petrol in one end and never open the hood taking the car to the nearest dealer at any sign of a problem, many have problems airing up there tyres, as with almost any other car. It is still a fact that the great majority of drivers have not got a clue what goes on under the hood, and do not want to know.

John (Britprius)

 

Hi all,

here's how I would go about solving oil loss issues:

1) Check the cylinder liners with a boroscope, especially the tops of them. If the crosshatch pattern is not there, there is no use proceeding further. The engine is shot and there are no wider pistons to use and have it rebored.

2) If all came out ok in the step above, I would check thoroughly for external oil leaks. Don't expect oil to drop on your driveway. If eg a crankshaft seal is shot, oil will come out only when driving and you will never see it. I had a problem like this with my other car. Thought it was burning oil until a crankshaft seal became completely shot and I had to replace it. VOILA!!! No oil burning! So, fix those leaks.

3) After fixing the leaks, wait to see what happens with the oil consumption. If there is still a problem, go after valve stem seals. They tend to be destroyed because of temperatures. They can be replaced without removing the engine. My bike was like that. The valve seals looked ok, but replacing them reduced oil consumption by 3/4.


Overall I tend to think that a well maintained engine does wear but only at very high miles. It's the rubber parts that fail (seals etc).

I would also suggest to not skimp on seal quality. Toyota sells some expensive seals but they are of the highest quality and I prefer them.


I hope this helps.