Mobil 1 is very good oil but I would hesitate to go beyond the recommended interval... not so much because of technical factors but because of human nature. As the first source notes in relation to Toyota's 6 cylinder sludge problem, "As is normal, a lot of people pushed the recommendation of 7,500 miles, servicing their engines at 10k mile intervals or often more, and the system didn't have enough of a 'buffer' to make up for this excess mileage. Delaying a 3k oil change interval is no big deal, as you are erring on the side of caution to begin with." So can it go 15K miles without problems? Probably. But if you are like us mortals the time to change the oil will come and go for a while. That reminds me: my wife's Prius has been saying to change the oil for a couple of weeks now. Time to do it, I guess.
I used Mobil 1 for many years but have recently switched to O'Reilley's house brand, promising myself I would not neglect the intervals. Huh.
There is no one with any experience -you could put the cheapest motor oil in your car run it 15k miles between changes and still get 200k out of a car - it is not like @ 15k miles the oil is going to suddenly quit working. What you need to think about is the value of the oil and extended ranges. If you are paying 3x as much for the oil and changing it 1/3 as often you are coming out ahead. but if you are going 3-5k on expensive oil is it really worth it. Honestly there are no bad oils anymore - the differences are almost negligible between a quality dino oil and synthetic unless you are in some kind of severe weather condition.
It depends on a few factors. Engine oils in part are lasting longer and longer because of things like better filter technology, but also because engines are cleaner than they used to be. So in a new engine the oil is going to last longer than in an older engine simply because the oil won't get contaminated as quickly in the new engine.
It also depends on how you drive. If you drive around and are often in high stress (acceleration) high heat, high rpm driving conditions the oil won't last as long as in a more conservative driving environment.
The best way is to check it every third time you fill your gas tank. When its black it's time to change it.
The oil is claimed to protect up to 15,000 miles. But please note that it's "up to" and all the things I listed above can greatly influence that range. It could be as low as 5,000km.
Heck in the race car we use mobile 1 and change it after every race. which is about 25 - 50 miles.
Doesn't the bottle say what the oil change interval is? If in doubt, send an oil sample to a lab. Remember that sending a sample to a lab increases your maintenance cost so just changing it when the Owner's Manual and the oil's bottles says, ie. 10,000 miles or six months, which ever comes first.
