However, generally speaking, a 2000 Ford Explorer likely recommends a conventional or synthetic blend motor oil. The viscosity will be indicated in the owner's manual, but common viscosities for that era were 5W-30 or 10W-30. Always use the weight recommended by Ford. Using the incorrect viscosity can damage your engine.
Don't rely on general advice found online; consult your owner's manual for the correct oil type and viscosity.