Full Synthetic 0W-20 engine oil change interval


Toyota ALSO has a conflict of interest, Whitey. The longer they stretch the oil change interval, the happier the EPA is, the lower the “total cost of ownership” appears, etc.

You’re making the assumption that the Engineering Dept is 100% responsible for the interval, and marketing, regulatory compliance, etc, are 0% responsible. That is naive.

For example, in the USA, where there are CAFE credits to score, 0/5w-20 oils are popular, to get an extra fraction of an MPG. In markets without CAFE credits, OTOH, the SAME ENGINE is often spec’d with 30 or 40 weight oils! Clearly, something OTHER THAN engineering optimization is afoot…


Whitey, if it were my own mother, I’d recommend she change the oil more often than the MFR recommends. In fact, I HAVE told my mom, in certain terms, that she ought to change the oil in her BMW X5 more often than the MFR states, assuming she intends to hold onto the car past 100,000 miles.

… despite the fact that SOMEBODY ELSE is doing the change, and I get NOTHING out if it.


If you think that’s bad, try getting a recommendation to replace struts that are only a few years old. One mechanic from Goodyear shop in Jacksonville told me I needed new struts. I responded, “Okay, that’s cool. The ones that are on there are covered by a lifetime warranty on parts, so just give me a quote on the labor.” Then he explained that they didn’t actually look bad, he was just recommending they be replaced because he thought they were the originals. What a dishonest jerk.


Does the EPA put money in Toyota’s pockets?

Why do I still see mechanics recommending 3,000 mile oil changes? Tell me that’s not dishonest while looking me straight in the eyes.

Well, in that case, I don’t think you have a conflict of interest, just mild paranoia and perhaps an unwillingness to accept new data. I always knew politics was tribal rather than fact-based. I never imagined car maintenance would be as well.


By contrast, when I asked the service manager at the Subaru dealership for an estimate of how much it would cost to replace all 4 struts on my '97 Outback, his response was, “I don’t recall ever changing struts on any of the cars that we service, even after 150k miles. Are you sure that you need struts?”.

Is it any wonder that I bought 2 more cars from them?


Not sure anyone was. I know dealers like that near hear…but I also know dealers that try to rip you off every chance they get. Some are good…some are bad.


A conflict of interest is a confluence of circumstances, not a particular behavior. The most widely-used definition is:

A conflict of interest is a set of circumstances that creates a risk that professional judgement or actions regarding a primary interest will be unduly influenced by a secondary interest.*

*Lo and Field (2009). The definition originally appeared in Thompson (1993).

For example, if a doctor prescribes a particular medication, and he happens to receive favors or money from that particular pharmaceutical company, he has a conflict of interest, even if he is prescribing the medication for the right reason.

Likewise, if I get a discount for personal use form a vendor, and then I recommend that same vendor for professional work at my job, I have an inherent conflict of interest, even if this is the best vendor for that particular service. I might be doing the right thing, and I might even be doing it for the right reason, but there is a conflict of interest present that I should avoid by using an impartial bidding process or by letting someone else choose the vendor who doesn’t have a conflict of interest.

So I’m not saying it’s necessarily wrong to recommend 5,000 mile oil changes for reasons other than the oil change being due, I’m just saying that, because it serves the mechanic’s or shop’s financial interest to shorten maintenance intervals, people should be honest about their reasons for doing it.


In other words everything is a conflict of interest. Doctor, lawyer, barber, mechanic, minister. Every win win relationship is a conflict of interest. It’s a black world out there. Consumer beware.


Two parts:

  1. Yes, it does. Any car maker that EXCEEDS its CAFE standards gets to SELL the excess on the open market to MFRs that fall short. (This is known as a “cap and trade” agreement.) Tesla, for example, is solvent today principally because it sells carbon credits, at great profit, to compensate for the production of vehicles, which hemorrhages money at a prolific clip!
  2. The EPA can directly COST Toyota money, should Toyota displease the EPA. This is the pessimist’s equivalent of “making money,” in that $1 million SAVED in fines is ultimately indistinguishable, in the bottom line, from $1 million EARNED.

All of this is EASILY searchable, Whitey, and the fact you are ignorant of it GREATLY UNDERMINES your argument.

Why do I still see mechanics recommending 3,000 mile oil changes? Tell me that’s not dishonest while looking me straight in the eyes.

Gee, Whitey, I never recommended a 3K mile interval, and I defy you to show me where I did. Nice strawman you got there…now, if it only had a brain!

Gee, Whitey, unlike you, I can readily produce five fact-based reasons to take present-day MFR recommendations with a jaundiced eye. Since you cannot (or at least HAVE not), I presume you are referring to yourself here?

Here goes:

  1. Toyota had a well-known, NOTORIOUS sludging problem that came about as a result of a new, “eco-friendly” engine design that ran warmer, to alleviate emissions, and over-heated oil as a side-effect and sludged engine blocks. The remedy for extant blocks was to shorten OCI.
  2. GM had an issue with Cobalt engines, where the cam chain was stretching unacceptably WITHIN THE WARRANTY PERIOD. The remedy was to re-program the oil life monitor to shorten OCI.
  3. Ford motor co, upon the advent of the CAFE scheme, “back-spec’d” many of their vehicles to 5w-20 oil. It should be noted that they ONLY went as far back as the EPA credited them with CAFE credits (7 years?)…any extant vehicle older than that was NOT back-spec’d, EVEN IF the engine were indistinguishable in design from one that was. (So, if you “trust the engineers”…which ones? The ones that BUILT it, or the ones that CASHED IN on CAFE credits, after the fact?)
  4. The new Diesel oil designation (API CK4) was reduced in ZDDP, for ecological reasons, and Ford found it INSUFFICIENT for some of their Diesels’ top end. They presently market their own Motorcraft oil that does NOT COMPLY with CK4 due to excess ZDDP. This begs the obvious question: if low-ZDDP is “insufficient” for one engine, is it “optimal” for any engine?
  5. MFRs often spec lifetime transmission fluids, even in cases where the company that initially built the transmission recommend a fluid change after a given number of miles. (There is one notable example; I’ll update this post when I track it down.) So, if you “trust the engineers,” WHICH ones do you trust? They can’t BOTH be right, you know!

LOL…you probably think ATF is truly “lifetime,” and hygroscopic (look it up, Whitey) brake fluid never has to be changed, because there isn’t a change interval in the owner’s manual…


You might want to look that one up yourself- it’s hygroscopic…


Ugh, right. I got re-directed by Google without realizing it. (I could be dishonset and claim “typo,” but I’m more ethical that that…)


…and unlike you, I can spell “manufacturer.” :wink:

Um, no, I don’t.

For the thousandth time, I don’t take issue with the recommendation, and I agree with the reasons, I’m just against lying to the customer about it.

I never thought saying “honesty is the best policy” would be so controversial in this group.

Not trusting the advancements in oil technology and engine manufacturing justifies getting a used oil analysis, but it doesn’t justify wasting resources, and it certainly doesn’t justify lying to customers.


Gee, Whitey, if the most glaring fault in my argument is that I’m overly fond of abbreviations…then I guess I’ve done a damn good job, haven’t I? Please note that spelling and strength of argument are not causally linked: “Wee huld teese trufs two bee self-evidint…”


Who thought you’d be so offended by my “don’t lie to the customer about your reasons” argument? Who knew that would be so counter-cultural in this forum?



Let’s have another oil change thread. What could possibly go wrong?


Who thought you’d be so offended by my “don’t lie to the customer about your reasons” argument

Again, see The Wizard about getting that strawman a brain.

I think you can make an argument (indeed, I HAVE) that a shorter-than-recommended oil change interval is desirable for people who place a high-than-average level of importance on extreme engine longevity. A used oil analysis is properly used to detect imminent failure, such as high lead implying bearing failure. Oil analysis is of limited to no usefulness in ONE vehicle for the purposes of OPTIMIZING wear; the errors are too high! (For a FLEET operation with thousands of vehicles, you have a point.) Oil analysis will tell you if your interval is in gross excess, but it won’t tell you if a shorter interval might be optimal.

…and there is little to no ecological damage associated with a shortened interval, provided you properly dispose of used oil, and practice good shop hygiene. Used oil is almost always recycled/reused when collected. The reason the EPA has its collective panties in such a twist is that a given percentage of people simply dump the stuff down the sewer! Thus, changing LESS oil reduces the amount of oil improperly disposed of, without changing personal behavior at all.

Just resolve to properly recycle your oil, and this concern is irrelevant to you, if not the EPA.


That not a straw man to point out that was the only position I’ve taken throughout this entire discussion.


The insinuation that I took exception to your argument is the Strawman, Whitey (or possibly the insinuation that the ONLY POSSIBLE reason to undercut the MFR’s oil change interval was for reasons other than longevity.)

…nobody was disagreeing that a mechanic ought to be above-board with his recommendations; yet, you keep insinuating that we were. THERE is your strawman.


It seems common that on car blog sites, very few people know some of the TRUE facts about the wonderful low-viscosity oils, which are more aptly called “water oils”, since they are about as thin as water.

Search for, or go to Castrol’s site, and read about it. You can dismiss what they say as sales talk, but it is not, and there are many mechanics, even Toyota Master Techs who agree that the use of 0W-20 oil is damaging to the engine.

The reason is that ‘water oil’ leaves almost no FILM on the cylinder walls, the rings, the bearings, and the overhead cam shaft. Castrol has found that it takes 20 minutes for a car to reach full operating temps and parameters, and that 75% of engine wear occurs when starting the engine after it has been sitting for hours. It doesn’t matter if it is winter or summer, particularly with water oils as they will just quickly leave parts without just about any lubrication.

It is also a known fact that Toyota has been making the same 2.5 L - DOHC 4 cyl engine design, called the AR, since 2008. From 2008 on, they all are basically identical with slight changes in hp. But they all are DOHC, 16V w/Dual VVT-i.

But, back in 2008 the recommended oil was 5W-20, when they began this foolishness solely to get more gas mileage to meet Federal CAFE higher mileage requirements. The other factor of making cars unsafe due to the absurd reduction in weight, effectively creating traveling tin cans of death, is whole other discussion that should be addressed in another post.

Toyota and other car mfrs. are making more MONEY by doing all this. They could care less about what is best for the engine; they simply want to cater to our Federal requirements, that are extremely misguided and myopic.

Many mechanics, even at Toyota, back in 2008-2010 or later, knew what nonsense water oils were, and they would use weights as high as 10W-30, and the engines operated just fine, and had a good film strength coating the engine parts. Even a 10W-30 synthetic is far from a thick oil. Toyota has done a dirty deed to their customers by demanding that 0W-20 be used, or the warranty is under threat. Ask a Toyota dealership now in 2017 to use another weight oil, and most simply will refuse to, regurgitating the same nonsense Toyota tells them - only 0W-20, and at 10,000 m. intervals. That is insanity. There are metal break-in shavings, and oil deteriorates over time, including synthetic, mostly from the byproducts produced from fuel combustion, which dirty the oil and filter, and are toxic to the engine.

The bottom line is: You don’t leave ANY oil in an engine for 10,000 miles, or you are greatly shortening the life of the engine. Furthermore, you shouldn’t use ‘water oil’ of 0W-20, but you are backed into a corner by Toyota, who is working against you, not for you. You literally have to find a dealer or a non-dealer shop to do your oil changes, and not print a receipt that shows they used anything other than 0W-20. You need to throw it right back at Toyota, and play games just like they do to protect yourself, as YOU are number one, NOT Toyota.


Same rant different site. http://www.toyotanation.com/forum/310-camry-7th-generation-2012-2017/1558690-toyota-s-claim-no-break-oil-change-wait-10k-many-strongly-disagree.html
Which site is next? May I suggest https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=cfrm or have you hit it already?