Is the Toyota 0w-20 recommendation for CAFE?

[SR5]

Originally Posted By: CR94
Originally Posted By: SR5
Very interesting, 50% increase in revs shows about 120% increase in heat load
That's perfectly logical, considering power loss in a bearing varies in proportion to speed squared, and 1.5 squared is 2.25.


Hi CR94,

Thanks for that and Welcome !!!

 

[Y_K]

Originally Posted By: MolaKule
By now and with plenty of history, we should have heard of all kinds of engine failures and engine replacements if the XW20 oils had failed to prevent wear.

Sienna 2013 had to swap its engine (and AT with 'lifetime' ATF) at 230k miles in taxi cab application in 2015. Running 24/7 by a crew, known for meticulous maintenance culture. Broadway Cab #995 in Portland, OR. Amzoil and M1 motor oil. Anybody can stop by the airport backfield and chat with them during a short break. Bought new. And just about 3 weeks ago another Sienna 2014 had the its engine swapped at 190k miles. Of course, this is not a statistically valid population sample, but this was unheard of in pre 0W-20 days. When cabbies bought a new CV in past, they could count on 600k miles of commercial service easily.
Admittedly, for regular users thinner oil may work well.

 

[edhackett]

Here's a link to the letter the EPA wrote to manufacturers in regards to their request to use 5W-20 oils for mileage and emission certification. It's an important part of the history of the use of thinner oils in the US.

https://iaspub.epa.gov/otaqpub/display_file.jsp?docid=14177&flag=1

Ed

 

[5170]

^^^
Seems straight forward. If you want to use 5w20 to gain CAFE kudos, you better make it the "preferred" oil used per the Owners Manual and fill cap, along with the other requirements set forth by the EPA. These requirements were established in 2000-2001. By 2016, there shouldn't be any question as to the suitability of an Xw20 if so recommended by the manufacturer.

Thank you for the interesting paper.

 

[Shannow]

Originally Posted By: CATERHAM

After a couple of years and the durability of this new engine oil was established, the reduced wear and fuel economy benefits was seen to be beneficial for all engines so Toyota, Honda and others started specifying the grade for non hybrid models as well. The rest as they say is history.


Got any links to the statements that these oils "reduced wear", and this being beneficial to "all engines"...and forming part of their decisions ?

Honda's papers always refer to "economy with satisfactory wear", not an improvement in wear.

Again, happy to learn, just link to a few papers...

 

[Shannow]

Originally Posted By: CATERHAM
Remember the Prius was first spec'd for the 5W-30 grade.
To quote Nippon Oil who worked with Toyota and Honda to develop a suitable "hybrid oil";
"increased wear resulted from the constant on/off action of the engine, thicker oil will not be able to warm up (to temperature) properly. This could lead to unnecessary damage and wear."


Here's a 400,000 mile disassembly of a Prius running 5W30.

http://www.api.org/~/media/Files/Certification/Engine-Oil-Diesel/Forms/Whats-New/9-DAP-Understanding-Lubricant-Requirements-of-Hybrid-Electric-Vehicles-DClarke-Infineum-USA.pdf

I'm looking for the damage and wear attributable to the 5W30 with 40-60 percent of the miles being engine off...

 

[RPMster]

Citing technical documents already referenced here, I'd have to agree that thicker oil does lead to less component wear over the life of an engine. For the average driver, however, the wear resulting from OEM-recommended 20 weight oil will be so minimal over 150,000 or 200,000 miles that it will really be of no consequence.

Fuel dilution will also come into play more with thinner oil for habitual short trip drivers. However, I believe this will also be of little consequence over the life of the engine, in most cases. To prove this either way would be a very tedious and very expensive experiment.

Where the real difference will come into play -- at least what I'd wager if I were a gamblin' man -- will be for "pedal to the metal" drivers who run their engines hard. I'm convinced that those engines will see more significant wear with 20 weight versus 30 or 40 weight oil, over the life of the engine.

For the drivers who flog the throttle on every commute, a worn out engine at 150,000+ miles will not be attributed to using 20 weight oil in most cases, so the point becomes moot.

However, will the sporty driver who runs 30 or 40 weight oil have a stronger engine at that mileage? I think we can say, with certainty: YES.

 

[Garak]

Originally Posted By: Shannow
Here's a 400,000 mile disassembly of a Prius running 5W30.

I guess we need to find what taxis are running. The Prius is now a common taxi. If it has become common, it's because it's cheap to run and reliable. They're clearly not dying at 150,000 miles. Now, are these taxi operators running a hybrid specific lubricant, or a dealer synthetic at all, or are they running whatever they can get cheap for themselves or at the quick lube?