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.
How often should a car's synthetic oil be changed? A: Synthetic car oil needs to be changed after 10,000 to 20,000 miles, depending on the climate and driving distances. The recommended non-synthetic oil change is every 3 months or 3,000 miles, whichever comes first. However, synthetic oils, which cost nearly twice as much as conventional oils, require less time between changes because of their ability to withstand high temperature levels.