Lots of old school thinking instilled in our brains.
Today's oils and today's engines are far more efficient.
BMW VW and many other, non American brands, having been running 15,000 mile
Oil change intervals on gasoline engines for well over a Decade without
Any problems.
A manufacturers recommendation at 10k miles is conservative they won't recommend something that will cause engine damage.
First oil change should not take place until 10k or earlier if computer states it's time to. Initial oil from factory is a very good oil with additives designed for break in to stay in engine and not be changed so early.
The Diesel engine is soo efficient I'm not surprised 18500 mile intervals are recommended. This engine is never revving high and never even working it ls just loafing nowhere near hard work.
Im not an internet troll, but i have to take you to task on this one. Almost everything you said if only partly true. To wit:
1. Synthetic oils are drastically more detergent than minerals. They get dirtier faster, because thats what they are designed to do. Better protection, cleaner engine, more contaminants in oil.
2. Extended oil change intervals sell cars, and influence Consumer Reports which also sells cars. But most of our engine internals are unchanged since 1950. And our pentastar engines have variable displacement oil pumps and both intake and exhaust valves are controlled by engine oil, along with piston squirters and oiled chains. Conclusion: modern engine are MORE sensitive to oil, not less.
3. You will never, ever, save enough money on oil changes to pay for that new engine!
4. Life of the vehicle is a subjective term these days. Companies like chevy and hyundai define it as 100,000 miles. Calling anything lifetime or service-free sells cars. Dodge tried this 10 years ago. They put a lifetime warranty on powertrains, reasoning that they would make more profit from selling more cars than the warranty claims would cost.
5. Change it first time 1000-2500, then every 5k after that. Look up my "topsider" post to seenhow to change it yourself without getting under it and without spilling a drop. If you drive all stop and ho, change it every 3k. If you expedite like me, 5k. All city stop and go is severe service!
6. Oems are in the business of selling new cars. So they design it to last 100k with zero maintenance. It will probably go 80k if you never change the oil, but not much farther.
7. Stick with one brand of oil for the life of the engine. Changing brands and weights only introduces incompatibilies with the additives which causes leaks and consumption.
Sorry to get on the soapbox, but it needs discussed. The oil change light in the pm has no information to go on other than hours and throttle angle. It doesnt have an optical sensor. It doesnt have an oil level sensor. It cant be trusted.