( 5W-20 ) is the recommended oil , according to the 2002 Ford Expedition Owner Guide
It should tell you on top of your oil fill neck on the engine. My Ford Escape does.
Type your answer here... how much oil in a ford expedition 2006 with oil filter change
The motor oil, in your 1998 Ford expedition, should be put in the oil fill tube. The oil fill tube should have a That labels it as the oil fill tube.
5W-20 ( according to the 2003 Ford Expedition Owner Guide )
( 5 w 30 ) according to the owners manual
According to the 2006 Ford Expedition Owner Guide ( 5W-20 )
The 1998 Ford Expedition Owner Guide shows ( 5W-30 )
According to the 2007 Ford Expedition Owner Guide ( 5W-20 )
The 2004 Ford Expedition Owner Guide shows ( 5W-20 )
The ( 1997 ) Ford Expedition Owner Guide shows ( 5W-30 )
It depend on what oil do you like using. I personally used Castrol 10W40. On my 1998 Ford Expedition XLT.