Ford F-650 Owner's Manual page 325

When to expect the message prompting you to change your oil
Interval
3000-4999 miles
(4000-7999 km)
Note: Use the appropriate special operating
condition for maintenance information
when using high sulfur diesel fuels,
operating your vehicle off-road or in dusty
conditions (such as unpaved roads).
Normal Maintenance Intervals
Gasoline Engines
Every 7500 miles (12000 km) or six months (whichever comes first)
Change the engine oil and filter.
*
Rotate the tires , inspect tire wear and measure tread depth.
Inspect the wheels and related components for abnormal noise, wear, looseness or
drag.
Perform a multi-point inspection (recommended).
*
Vehicles with dual rear wheels should rotate the front wheels when specified; rear wheels
only if unusual wear is noted.
F650750 (TBC), enUSA, First Printing
Scheduled Maintenance
Moderate to heavy load or towing
Mountainous or off-road conditions
Extended idling
Extended hot or cold operation
Maximum load or towing
Extreme hot or cold operation
Use of high sulfur diesel fuel
322
I n f o r ma t i o n P r o v i d e d b y :
Vehicle use and example
Extreme