5W-30 is the PREFERRED oil
I assume it is the same as the ( 1996 ) Mercury Villager : With engine oil filter change : ( 4.2 US. quarts of 5W-30 engine oil )
right above the oil filter on the transmission side of the filter mount
without oil filter 3.7 quarts with oil filter 4.2 quarts
Valve cover gasket?
5W-30 is the preferred oil ( according to the 1996 Mercury Villager Owner Guide )
According to fordparts.com : For a 1995 Mercury Villager : Engine oil filter ( Motorcraft FL - 839 ) Engine air filter ( Motorcraft FA - 1121 ) Engine fuel filter ( Motorcraft FG - 978 )
According to the 1998 Mercury Villager Owner Guide ( 5W-30 ) is the preferred oil