Ford 2002 F650 Owner's Manual page 185

Engine oil and filter recommendations—7.3L Power Stroke engine
To help achieve proper engine performance and durability, it is important
that you:
• Use only engine lubricating oils and oil filters of the proper quality.
• Change the engine oil and filter no later than the recommended
service interval. Refer to the Scheduled Maintenance Guide for the
appropriate intervals for changing the engine oil and filter.
• Change your engine oil and filter more frequently if your vehicle
operation includes extended periods of idling or low-speed operation,
driving for a long time in cold temperatures or short driving distances.
Diesel engines require specially formulated oil to resist contamination.
Proper quality oils also provide maximum efficiency of the crankcase
ventilation system which reduces air pollution.
For normal or severe service, use Motorcraft oil or an equivalent oil
conforming to Ford Specification WSS-M2C171–C or API Service
categories CH-4, CH-4/SJ or CH-4/SL. If CH-4 oil is not available, CG-4 is
acceptable.
Diesel engine oils with improved fuel economy properties (energy
conserving) are currently available. If you use an energy conserving oil,
be sure it meets Ford specification WSS-M2C171–C or API service
category designation CH-4/SJ and is of the proper viscosity grade for the
temperature range in which you expect to operate your vehicle. Some
energy conserving oils do not meet the requirements necessary for your
diesel engine.
Maintenance and Specifications
185