LOL, I'm wondering what oil to go with on my '06 4.0 4X4 V-6. It's not showing any signs of using oil or anything. However, it's 'using' coolant. I'm having to add a half-gallon of coolant for every 2K miles of driving. I'm TRYING to get it sealed-up, but not sure why it's using some coolant. I can only assume it's going by the heads, but not enough to make it a big fix needed.
Won't matter what oil you use, if you let that coolant leak go much longer & burn up the engine.
The V6~4.0L~SOHC is notorious for leaking coolant from the junk Plastic ThermoStatHousing
that Ford designed+used & similar versions that are sold by most parts stores.
Have you thoroughly inspected around the ThermoStatHousing & under the IntakeManifold for a coolant leak?
Often the plastic Housing only leaks when the engine gets hot, back into the "cave" under the Intake,
then the Coolant evaporates on the hot engine block before leaking onto the ground.
If you've never replaced the original 15+ year old ThermoStatHousing, that would be a prime suspect.
Strongly recommend replacing plastic Housing with an Aluminum version.
If the ThermoStatHousing is NOT leaking, there are several other suspects:
~ junk Plastic HeaterControlValve
~ junk Plastic HeaterHoseTee
~ junk PlasticTanked Radiator
~ WaterPump
~ Hoses+Clamps
~ HeaterCore
If you've not replaced any\all of the above original 15+ year old Coolant system components,
they are all suspect & you should consider a Coolant system makeover with all new parts.
More info at
https://2001fordexplorersporttrac.fandom.com/Engine_Coolant_ThermoStathttps://2001fordexplorersporttrac.fandom.com/Engine_Coolant_HeaterValvehttps://2001fordexplorersporttrac.fandom.com/Engine_Coolant_Radiator+Caphttps://2001fordexplorersporttrac.fandom.com/Engine_Coolant_Fan+Clutch+Pumphttps://2001fordexplorersporttrac.fandom.com/Engine_Coolant