Synthetic oils can do that.

No expert is going to suggest any normal car should operate for 26,000mi per oil change. Even modern synthetics and modern engines recommend 7,500 or so miles, and can often be stretched for a bit over 10,000mi, but 26,000mi as a normal interval is way beyond that.

My modern car recommends synthetic changes at 7,500 miles by the book. Sending off samples to the labs, it looked good at that point but started to get some bad degradation at about 11,000mi. It would be sludge a little after 15,000mi and would have probably destroyed the engine before 25,000mi

Not all synthetics can do that of course, but some can. There are people who have gone several hundred thousand miles without an oil change and an oil analysis says they are still good.

Oil analysis is about the cost of an oil change for most people and sometimes says change the oil so most people just change the oil. For some it makes sense to do oil analysis.

Please show me a single car manual for an ICE advising a 26,000mi oil change interval or any normal motor oil sold advertising its good for 26,000mi.

Otherwise you're talking about extremely rare one-off cases where someone's car happened to be in just the right environment and built just perfectly the whole time. I'm not talking about "that one time one guy in a forum five years ago said his car lasted 120,000mi without an oil change", I'm talking about normal advice for normal car drivers.

https://www.amsoil.com/ their 25000 mile oil when combined with their bypass filter and regular oil tests.

No OEM car manual says this is recommended.

Crazy to see them recommend it, but they do:

> Normal Service – Up to 25,000 miles (40,200 km), 700 hours of operation or one year, whichever comes first, in personal vehicles not operating under severe service.

That said, this still goes against the person who I was originally commenting about. They suggested going 2+ years between oil changes, and while the mileage does fit here for the average car the timeframe doesn't.

You're also technically 1,000mi short from my ask but I'll grant if it actually is OK at 25,000mi it's probably still OK at 26,000mi.

You missed the bypass filter. If you add that to your engine you can replace the yearly / 25000 oil change with oil analysis, if that comes out okay just change the filters (replacing only the oil in the filter), thus not doing a full oil change. . If you only use their oil then 25000 miles is 1000 miles short.

For most people oil analysis and their filters is more expensive than just changing the oil.