According to one of Fords websites :
The 1998 Mercury Villager uses the ( Motorcraft RS-519 radiator cap )
It is a ( 13 PSI cap )
Look on the bottom or rear of the radiator or just remove the lower radiator hose
If you mean the oil pressure sender it's right next to the oil filter.
It should be the same.
The low pressure port on a 1998 Mercury mountaineer is located on top of the ac drier. The drier is mounted close to the radiator on the passenger side.
According to the 1998 Mercury Villager Owner Guide ( 5W-30 ) is the preferred oil
10w30
The 3.0 litre V6 engine in a 1998 Mercury Villager has a timing BELT
R134
on my 1999 ford mercury villager its on top of transmission under the van
The distributor in a Mercury Villager is the round thing at the front of the engine with the six spark plug wires attached to it.
The Villager has an electric fan and does not use a "fan belt".
The 1998 Mercury Villager 3.0 liter V6 engine has a timing BELT ( according to the Gates website , they make timing belts etc. )