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Subject:  Re: Age of fluids Date:  3/16/2013  3:42 PM
Author:  havefunsaving Number:  69911 of 73163

So my question: with a brand-new car, one that I intend to keep for 10 years or so, one that I intend to maintain religiously to get the most out of the car for the longest period of time possible: Is there any advantage whatsoever to changing the oil more frequently than 10K miles? - Me

In looking for more info (and trying to answer my own question to some extent), I found this from a link in Post #69814 by dbruce100 (emphasis mine):

While the wear rate is not greatly escalated at the front end of the OCI, it certainly is not relieved (lessened) by the frequent OCI, either. In short, changing your oil early does not reduce the wear rates, presuming you did not allow the sump load to become compromised in the previous load. It’s a subtle but very important distinction. When you have reasonably healthy oil, the wear rate slope is generally negatively flat (muted is a better term, as there is always some variance). Only after the oil becomes compromised (overwhelmed) in some manner would you see a statistical shift in wear rates. Hence, higher wear at the front of an OCI is plausible, but the claim of lesser wear with fresh oil is most certainly false. The wear rate for Fe is reasonably constant, if all other things are in decent operational shape. Those who change oil frequently at 3k miles are not helping their engine. Those who leave it in for longer periods are not hurting the engine. At this point, I will note an acknowledgment to the concerns outside of wear metals. Oxidation, soot, coolant, fuel, etc can cause a need to OCI. But, those things are also reasonably tracked in a UOA. So, if your fluid health is good, and your wear metals are on track, there is no reason to OCI until something changes in a statistically significant manner.

Now if you click on the linked article, you will see that that section is talking about a specific engine (the Ford 4.6L, "modular" gasoline V-8 engine), but I'm guessing it goes to the heart of oil changes in general:

In addressing the UL listing for that engine,and utilizing various oil types, etc., within the sample, he said:

Hence, the conclusion to come to is that lube brand and grade, filtration selection, as well as various service factors and OCI [oil change interval] durations, really don’t matter greatly in this example; the 4.6L engine really does not care what you use or how you drive it.

If you read the section on the Toyota engine, it's short and to the point. It suggests that that particular engine wears really well at longer OCIs.

So, to get back to my question, I suppose it matters which engine I'm talking about, as much as which car. Nevertheless, the above suggests that I should consider following the car manual's suggested OCIs, as they were presumably arrived at after much testing -- and on the theory that the car manufacturer would not intentionally mislead the car owner on maintenance intervals.

Best regards,
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