How did they "fail"? Were they clogged with crap? If they were, then oil has everything to do with it. Especially if it was crappy oil that was allowed to remain in the engine for 10,000 miles. I'd say oil has PLENTY to do with this.
If these things are failing because of a "bad design", we would be hearing about it, and seeing this everywhere. Was there a TSB ever issued pertaining to "faulty oil squirters" in Toyota engines? He would have mentioned that. No, he didn't because there wasn't...... 10,000 mile crappy oil, you betcha.
Even if the oil was changed with TGMO, the quality of the lube would at least be suspect. In a post made some time ago,
@OVERKILL described the quality of the Toyota oil. Notwithstanding that the oil is supposedly made by Mobil, it is made to Toyota specs and
@OVERKILL mentioned that thinner, lower quality, base stocks and plenty of viscosity improvers are used to create the package.
Other oils may have similar problems negating their value for use in many 10,000 mile OCIs.
One of the things that is often heard here on BITOG is that if an oil "meets the spec" it's good enough. Having spent a day at HPL listening to some real experts describe how oil is formulated, tested, and used, I now believe even more firmly that meeting the spec, at least wrt API certifications, and extending drain intervals to 10,000 miles, is just asking for trouble
in the long term.
Even The Care Care Nut, who is an advocate for all things emblazoned with the Toyota logo, cautions us to keep the OCIs to 5,000 miles / 6 months if you want long-term longevity. I don't believe he's wrong about that since most people are using their cars in what may be considered "severe service" and the oil that they're using, even the oil with the latest API certs, is of minimum quality.
The oil experts at HPL (not those that work at or directly for HPL, but outside consultants) explained that in order to obtain API certification the oil must pass certain tests. However, if the oil fails the test(s), it's allowed to be tested and retested until it passes. Some API oils fail more than once until achieving a passing grade. As one of the panel asked, do you want an oil that only passes 1X out of three or four attempts?
Another interesting factoid is that some oils are formulated using waste oil. Allow me to explain (and please, if I'm mistaken on this, Dave or anyone else who was there, correct me. I'm sure I've the concept right but might be mistaken on terminology or some minor details).
After a batch of oil is processed, the tanks and equipment are cleaned by running some oil through them. This oil is called a wash, and that wash oil is purchased by some companies to use in formulating their own oil, the stuff you buy off the shelf at places like Seven-11, Walmart, and the like. In some instances, this wash isn't even treated and properly cleaned before being mixed with additives and packaged for sale. Some of you may be buying oil made in this manner if you're looking for bargain-priced oil ... or maybe not so bargain-priced.
I came away from the weekend at HPL with a deeper understanding of what goes into making a jug of oil, of how complex the formulations can be, and how, because of the way the certification process works, there's little to no incentive for a company (not all companies, and not in all instances) to produce a product that excels. Good enough is good enough.
So, if you want longevity from your engine, it seems there are a couple of options: change at reasonable intervals (less than 10,00 miles with API oils) or use higher quality oil. I guess it comes down to "you pay your money and you make your choice."
