In a Ford Explorer :
The 4.0 liter V6 engine ( both the Over Head Valve and the Single Over Head
Cam versions ) have always used :
( 5W-30 , with engine oil filter change , 4.7 litres / 5.0 U.S. quarts )
According to the 1999 Ford Explorer Owner Guide ( 5W-30 ) is used in all the engines
I have always used Castrol Motor Oil in all my Vehicles. 10W30 or 10W40 ( the Owner Guide shows 5W-30 is the preferred oil , that's what I have used in my 1995 Ford Explorer XLT for 15 years )
If you have the owner's manual, it usually says what kind of oil you need in there.
( 5W-30 ) according to the 1997 Ford Explorer Owner Guide
5W-30 is the preferred oil according to the Owner Guide
Ford uses the Motorcraft blended oil (part synthetic).
SAE 10w30
5W-30 is the preferred oil ( that's what I've used in my 1995 Ford Explorer since 1995 )
The preferred oil is 5 W - 30
According to my Haynes Ford Explorer repair manual : ( MERCON automatic transmission fluid is used in the transfer case of a 1993 Ford Explorer )
5W30 , according to the Owner Guide
( No ) on a 2002 Ford Explorer the oil pump is mechanically driven