Oil Burning Prius...Common Factors?

Piston ring coking.
Down with TGMO.

 

there might be, but without a roundup of a statistically relevant quantity of owners, it's impossible to know. and many owners are second hand.

 

Not to turn this into a BITOG, TGMO flame war, but my 2010 is perfect on nothing but TGMO at 5k intervals since day 1. Oil level on the stick doesn't budge the entire interval and the car is just a tick under 120k miles. Being in tune with the potential for issues with these engines has made it so I'm scared to try another 0w-20! I know this is irrational as all the full syn 0w-20's are known (or thought to be) quality oils. Don't you think TGMO is at least in line with M1 AFE, or does the propping up of the V.I. turn you off?

Toyota has had oil burning issues, even if isolated, with the straight-4, Z-FE engines since the late 90's at least. I generalize here because they are all somewhat closely related, many sharing the same bottom end. I'm guessing top ends share similar design theory across the line, even with the simulated atkinsons. It's easy to find documented Corolla tear downs with ring coking AND clogged piston return holes but many of these date back to pre-TGMO. Even the gen 2 Prius was spec'd 5w30 conventional and I think they mostly all tend to burn as they age.

Anyway, I'm thinking the issue has more to do with hot running and/or somewhat oil starved top ends doing a bit too long, or too severe of an interval vs. quality of the oil. freindly_jacek's survey doesn't really support this theory but a Priuschat survey doesn't likely represent much of cross section of typical owners, either. I won't do a 10k OCI on these engines or the MZ-FE V-6's, even with an extended drain synthetic. I also fear unscrupulous dealers, quickie lubes and independents dumping whatever weight conventional in them and oblivious owners tooling around for 10k miles, let alone 5k... I feel these engines lean toward 5k syn and only syn, 3k conventional OCI's for Gen 2 with 5k syn being a better call, regardless of what Toyota, and the industry in general are spec'ing. For those that don't change their own oil and are getting away with 10k OCI's without burn issues, I'd guess they are getting a synthetic oil and/or the burning hasn't taken hold yet.

As an additional note, my '07 (160k miles) burns 16-20 oz.'s BC (GC) 0w-30 at 5k OCI.


For the non-BITOGer's :

BITOG = Bob is the Oil Guy

TGMO = Toyota Genuine Motor Oil, 0w-20 specifically, blended to Toyota spec by Mobil 1 in the U.S. Viewed as similar to Mobil 1 AFE but with a very high viscosity index. At a time very popular with the BITOGer's but has fallen out of favor for whatever reasons...

BC (GC) 0w-30 = Castrol Edge Syntec Euro spec, long time blended in Germany, recently moved to Belgium. Another BITOG favorite which has also faded from the limelight.

V.I. = viscosity index

OCI = oil change interval

 

I think many Prius cars burn oil but not enough owners actually check to find out if they do or not. I would say there's probably a higher percentage that burns oil vs. ones that don't. Many factors contribute to that and nobody has been able to pinpoint the main reason(s).

 

@m.wynn , thanks for clarifying all the damn acronyms. I hate it when everyone starts talking another language, lol.

I've used nothing but Toyota OW-20, changing it at 8000 km or 6 month intervals. Currently a mere 60,000~ km on the odometer, no apparent consumption between oil changes. Kind of eerie actually, all our Honda's would consume somewhere between a cup and a pint, between changes.

 

In BITOG terminology, this makes you a TGMO fanboy. I'm right there with you!

 

And that's giving the quick lubes the benefit of the doubt. I guess I rate the dealers and independents a step up from the quickies, but really cringe at the thought of anyone aside from myself selecting and changing my oil. Places get busted for not changing at all. Imagine these engines (or any engines) going 20k, or more, on some bulk conventional... Blame it on my OCD, baby!

OCD = obsessive compulsive disorder

 

OK. The cause is viscosity index improvers(VII).

I am the Sustina pioneer. Sustina (HTHS 2.60) has much lower VII dosage, and superior overall design than Toyota Genuine Motor Oil (HTHS 2.62).

Current fill is Ravenol 0W16 (HTHS 2.4). 40k miles total have been driven, with oil change intervals extended beyond 10k miles.

From now on, it will probably be overkill. Mobil 1 EP 0W20 (HTHS 2.7) with oil change intervals less than 10k miles.

My thinking is to use highest quality, even thickish 0W20 motor oils. Know the design and thickness of your motor oil !!

HTHS=high temperature high shear. Higher is thicker.

 

Another possible factor? The 3rd gen has a somewhat unorthodox oil filter, where just the element is changed. That means less material to deal with, easier to recycle. On the other hand, it's also more prone to neglect. It is way too easy to forget to put a new filter in; I've caught myself about to spin it back on sans filter, twice. If it's pros changing your oil, it's impossible to verify the filter was changed, or forgotten.

 

Failure on the part of owners to properly maintain.

 

very possible.

 

I'll guess that's encouraged by habitually pushing the engine hard --- as in sustained high speed, climbing long mountain grades fast, etc. Right?

 

Agreed. That would have to be a factor.

 

That's called severe duty cycle and even Toyota's minimum recommendation says change before 10K miles under those circumstances...if one is a minimalist that is. Toyota's 1.5 and 1.8 liter engines are proven in more than just the Prius with no know issues.

I repeat...Failure on the part of owners to properly maintain.

 

Would oil change every 6K be neglect? That's what I've been doing.

 

What does your Owner's Manual say? Where in the world are you? Italy?

Keep in mind too: the interval is distance or time, whichever comes first.

 

I've heard that changing the PCV valve helps resolve the burning oil issue, but its also important to maintain 5K oil changes (I don't trust those 10K oil intervals).
I've been trusting my vehicle with Kendall Motor Oil with Liquid Titanium 0W-20.

 

Failure to monitor level and usage also is neglect. Don't tale it personal, but people in general now days just don't tend to their vehicles like years past. Whether it's because you HAD TO back then or because people just have not been taught car skills makes no difference...complacency, apathy and blind trust still bite just as hard.