Before this big, bad pickup arrived, manufacturers largely used upgraded versions of their light-duty trucks to handle heavy-duty work. The 1999 Super Duty was a separate model line with its own style and hardware underneath.
You can run a conventional oil 5K miles but you should be able to run a synthetic oil 7500 to 10000 miles. Royal Purple API-licensed synthetic engine oils allow motorists to travel as many as 12,000 miles as the recommended oil change interval.
I know the regular oil they tell you to change it at 3k miles but im pretty sure its ok to go to 4 or even 5k miles, yes? SO im wondering about synthetic oil in my 2012 corolla and how many miles is safe to go over without changing it You could change 100% synthetic oil at 6-9k miles and not have a problem (synthetic blends and regular dino oil at less mileage).