However, generally speaking, Ford often recommends 5W-20 or 5W-30 conventional or synthetic motor oil for its vehicles from that era. The specific viscosity (like 5W-20 vs 5W-30) will be detailed in your owner's manual. It's crucial to use the correct viscosity to ensure proper engine lubrication and performance.
Do not rely solely on this information. Check your owner's manual for the precise oil type and specifications recommended by Ford for your specific 2004 Ford Expedition's engine. The manual will also list the recommended oil capacity.