This vehicle comes with 3 different engines. You have neglected to tell us which.
It is to the left of the oil filter, you can use a small 1/4 inchthreaded plug to put in there if it leaks. Be careful it is fragile.
worn crankshaft bearings
yes... It could also be the oil sending unit or the oil pressure switch.
Bad sending unit, low oil, low oil pressure.
Minimum pressure would be 15 psi at idle.
i believe it is a 9/16 wrench, or 14/15mm if metric.
Less cheeky answer: 4.5 quarts with an oil filter change, 4.0 quarts without (pg. 186 of 1995 Plymouth Voyager Manual). Try not to overfill; that could aerate your oil and make you lose oil pressure.
The oil sensor is on the forward side of the block ,just above the oil filter
what do I need to change the 1997 Plymouth voyager transmission oil
The low oil pressure light would be on if you had low or no oil pressure. If you question the accuracy of the oil pressure light, a mechanical gauge could be installed permanently or temporarily to double check pressure readings.