FORD 2001 Explorer - Manual (Page 213)

Engine Oil Recommendations
5.0L Engine
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SAE 5W-20 engine oil is recommended.
Only use oils “Certified For Gasoline Engines” by the American
Petroleum Institute (API). Use Motorcraft (Part: XO–5W20–QSP in U.S.)
or an equivalent oil meeting Ford Specification WSS-M2C153–H. SAE
5W-20 oil provides optimum fuel economy and durability
performance meeting all requirements for your vehicle’s engine.
Change your engine oil and filter according to the appropriate schedule
listed in the scheduled maintenance guide.
Do not use supplemental engine oil additives, oil treatments or engine
treatments. They are unnecessary and could, under certain conditions,
lead to engine damage which is not covered by your warranty.
4.0L Engine
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Maintenance and care
213