10K oil changes are BAD! ??

That's the key right there ... Toyota's manuals define severe service criteria, you're on the honor system to decide if your driving falls under them, and if so, 5k is the Toyota-specified oil change interval, period.

 

Yep my wife's 2017 Prius usually has only 1,500-2,500 miles after 6-months of driving but I change it out, anyway. My 2021 gets 5,000 miles in 3-4 months (my commuter car) so she goes by mileage. My Tundra also only gets around 5,000 miles a year but, still, changed every 6-months. (She's a 2014 and only has 45,000 miles on her.)

 

That's a whole lot of little used, fairly clean, expensive oil getting dumped into the recycle stream,,, hopefully.
And a big added expense, especially if you are paying for this service.
But your vehicles are happy!

Somehow, 6 month intervals, regardless of miles seems weird.
Maybe ok if the car only gets used for short trips and never warms the oil all the way up.

 

Just curious for you or anyone else that does 10k oil changes, but what does the oil look like on the stick at 10K? Mine gets very black after a 3k but it's super high mileage.

 

But which used vehicle would you prefer to buy?

 

Oh I do all of the maintenance on our vehicles, so I'm always looking for sales on 5-qt jugs of synthetic oil, but I prefer Mobile 1 and Valvoline, so will grab those if nothing is on sale. An oil change probably runs me less than $30 since I also stock up on oil filters. O'Reillys and AutoZone recycles my oil drain pan when it gets full. I can knock out the oil change in a vehicle in less than 30 minutes with the drive-on ramps.

 

Yep, these Toyota engines have impressed me. Years ago, we had a Chrysler Van and the oil would be as black a night after just 2,000 miles....I've never seen that in a Toyota even when they have closer to 10,000 miles.

 

Love bringing new cars into an older car threads to form conclusive results.

 

Grit,
Making an easy to understand conclusive statement......

 

That's an interesting point....did the folks who only did oil changes at 10,000 miles, and had engine issues, only have their car serviced at places who use the cheapest bulk-oil they can find? (Jiffy Lube/Walmart Service Center/Grease Monkey/Dealerships)
Since my local auto parts stores don't seem to be having as many sales on synthetic oils, I'm probably going to be buying it at Costco...two 5-Qt jugs of 0W-20 is $39.99 so that's $3.99 a Qt. (Kirkland is the brand and they also make the Amazon Basic oil which I've used...good stuff.)

 

@Mendel Leisk he retired from the dealership and now runs his own shop called I believe TCCN Automotive.

 

I spent quite some time Saturday searching out oil sample results online and made some interesting discoveries. PQIA.org did new oil analysis on 0W-20, including Toyota’s and MobileOne. The Toyota sample was quite impressive and better than MobileOne.
They only had one 0W-16, Pennzoil Hybrid, that was informative.
I also found some new oil sample comparisons that included 0W-16 and compared Toyota’s with several other brands and once again Toyota faired better, especially in additives and viscosity stability.
FWIW, I saw enough to tell me two things: I’m sticking with Toyota oil and if a dealership does put 0W-20 in my 2022, it is so close to the specs of the 0W-16 that changing it back per the maintenance schedule will be fine.

 

I used to think that too and here's a spreadsheet I made to that effect:




But I have since learned that Virgin Oil Analyses are not quite that informative. For instance a high viscosity index for the same grade of oil (e.g. 0W20) is not necessarily a good thing. The higher the VI, the less an oil's viscosity changes over wide temperatures - which is great. The problem is that a cheaper base oil (Toyota 0W20) relying heavily on viscosity index improver (VIIs) additives to achieve this stable viscosity often looks better on a VOA than an oil (Mobil1) relying on higher quality base oils. But those VII additives wear out very quickly which makes it bad for extended drain intervals.

You can especially see Toyota oil's inferiority (compared to Mobil1) in the volatility mass loss of 12.9% which is just *barely* under GM's original 13% Dexos 1 standard (ILSAC GF-5 spec is less stringent at under 15%). Toyota 0W20 actually fails the current gen 3 dexos 1 standard of 12.5. It loses 33% more oil to evaporation/burn off than Mobil 1 (and 57% more than Pennzoil Platinum!). That means more deposits left behind (on oil rings and oil drain holes).

Toyota does use a ton of Moly, but the oil analysis doesn't tell you how good Toyota's particular moly compound is - just the raw ppm count.

 

Do you remember when you made the spreadsheet? What you point is based on Toyota oil using “a cheaper base oil”. So my first question is “do you have evidence of that beyond velocity mass loss numbers?” Another point is you don’t mention TBN.

 

I made the spreadsheet a few months ago from the data on PQIA and then spent a few weeks going down the rabbit hole at the Bob Is The Oil Guy forum. From there I learned Toyota (Exxon/Mobil) uses a Group III base for Toyota Genuine Motor Oil (TGMO) while Mobil 1 uses a Group IV base (though there are indications they may be starting to blend in Group III) and Pennzoil's synthetics use a GTL base.

Group III is highly refined crude oil that really isn't synthetic, but is marketed as such. Group IV is a true synthetic created in a laboratory and costs much more to produce. GTL is gas-to-liquid which is more akin to a highly refined crude except it doesn't start out with as many impurities.

One of the signs of a group III oil is a relatively high NOACK (mass volatility) compared to Group IV (PAO):


Another is slightly lower oxidation stability:



It gets a lot more complicated because a good group III base with a great additive pack can be a better oil than a good group IV base with a mediocre additive pack. Toyota's oil is among the best group III's and from the bottle it performs extremely well (marginal NOACK notwithstanding).

My issue with TGMO is that it doesn't hold up particularly well for most people beyond 5,000 miles. It is very common to see marginal or substandard flash points & 100C viscosity starting to occur between 5-10,000 miles:

Prius Prime with 7,000 KMs (and less than 2,000 KM with ICE running) and substandard viscosity:


Corolla AE85 with ~5,000 miles and substandard flashpoint:



4Runner with ~3,500 miles and substandard flashpoint:


At the limit flashpoint after < 3,000 miles on this Tacoma (which was towing a 1,200 lb trailer):


Marginal flashpoint after 9,000 KMs on this GS350:


Bad flashpoint after 6,500 miles in a Honda Odyssey:


There are some people with ~10,000 mile samples that look decent, but they're the exception and tend to be high-mile drivers (i.e. the people who actually fit the criteria for extended oil drain intervals):

10,000 mile OCIs on Elantra (note that on this guy's history you can see when TGMO switched from lower moly to current high moly formulation):


Toyota's Base number does start off high, but you can see it breaks down fairly rapidly. This seems to happen more with the new (2018+) high-moly formulation.

 

Thank you, that’s very helpful, do you have any info on the 0W-16 oil in that regard? Another piece of info I could use some help with is the’22 maintenance schedule states “driving on dirt roads or dusty roads” as quality as needing 5k or 6 months OCI, but when I went to Toyota.com’s owners site for my “5000 mile” service, “roads with melted snow” (or something to that effect) was added. Do you happen to have any info on that change?
Thank You for your help.

 

I don't. In fact, the more I looked into 0W20, the less enthused I was about its purported benefits over 5W20 or 5W30. The fuel efficiency gains are miniscule - Mobil1 says a 0.2-2.3% mpg improvement compared to heavier grades (0.2% presumably being the gain over 5W20 and 2.3% presumably being the gain over 20W50).

From my research, the push to 0W20 (and now 0W16) was largely inspired by the EPA's adoption of the 5-cycle fuel economy test, specifically the cold "city" drive cycle which is conducted on a dyno at 20F:





Historically the EPA had one highway test and one city test - both conducted on a dyno at a controlled temperature of 75F with the engine warm and the heater & AC off. These tests date back to the 70s and worked reasonably well after a minor correction factor was applied in the 80s. But then the Insight and Prius came out with astronomical EPA ratings which almost no one could achieve. The 2nd gen Prius was extremely popular and hundreds of thousands of consumers were furious that they couldn't get anywhere near the EPA's 60mpg city, 51mpg highway rating.

So the EPA did a bunch of studying and added 3 new cycles - a higher speed (80mph) test, a hotter test (95F with A/C on), and a cold test (20F with heater on) to try and get their test results to match what consumers were getting in the real world.

Long story short, 0W20 oil (and now 0W16) are really meant to help game the numbers on that 1 cold cycle EPA test. If you live in a colder climate (like northern Illinois in the winter) that may translate to noticeable improvements in the real world. But 0W20 makes no noticeable difference in mpg over 5W30 in California's central valley in the summer. This is probably why Prius owners manuals from elsewhere around the globe allow 0W20, 5W20, 5W30, & 10W30:



Anyway, I have been impressed that I haven't seen more bearing or cylinder wear on engines running 0W20, but I'm not tempted to experiment with 0W16 just yet. I'll wait a few more years to see how engines running it look after 300,000 miles...

I don't have any info on that change, but it makes sense to me. Thankfully I haven't driven regularly in ice & snow in a number of years, but when I did my car would be filthy in no time. So it is plain to me that snow-melt road mist is much, much dirtier than rain mist. Mist goes into your air intake and while much of the dirt is stopped by the air filter, we know some will get by (just like on a dusty road).