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.
Myth: Once you switch to synthetic oil, you can never switch back. 1  Myth: Synthetic motor oil is not compatible with conventional motor oil. 2  Myth: If you use a good synthetic oil, you can change your oil less frequently. 3  Myth: You shouldnât use synthetic oil in an older vehicle.