FORD 2003 Explorer v.2 - Manual (Page 230)

3. Recheck the engine oil level. Make sure the oil level is not above the
MAX hole on the engine oil level indicator (dipstick).
4. Install the indicator and ensure it is fully seated.
5. Fully install the engine oil filler cap by turning the filler cap clockwise
1/4 of a turn or until three clicks can be heard.
To avoid possible oil loss, DO NOT operate the vehicle with the
engine oil level indicator and/or the engine oil filler cap removed.
Engine Oil Recommendations
4.6L Engine
Look for this certification
trademark.
SAE 5W-20 engine oil is recommended.
Only use oils “Certified For Gasoline Engines” by the American
Petroleum Institute (API). Use Motorcraft 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.
Maintenance and Specifications
230