That all depends on which model of ranger you have,
using the info from the 1988 truck light duty specification book,
it states;
all short wheel base vehicles with midship mounting gas tank 57.5 litres
all long wheel base vehicles with midship mounting gas tank 64.4 litres
all Ranger Super Cab vehicles with midship mounting gas tank 54.9 litres
Optional Auxiliary Aft of Axle mounting gas tank 40.2 litres
Engine size doesn't seem to affect gas tank capacity.
With engine oil filter change : The 2.3 liter DOHC engine is ( 3.8 liters / 4.0 quarts ) The 3.0 liter V6 engine is ( 4.3 liters / 4.5 quarts ) The 4.0 liter V6 engine is ( 4.7 liters / 5.0 quarts ) According to the 2001 Ford Ranger Owner Guide
With engine oil filter change : The 2.5 liter 4 cylinder engine takes ( 4.5 quarts / 4.3 liters ) The 3.0 liter V6 engine takes ( 4.5 quarts / 4.3 liters ) The 4.0 liter V6 engine takes ( 5.0 quarts / 4.7 liters )
The 2.3 liter 4 cylinder engine in a 2008 Ford Ranger takes : ( 3.8 liters with engine oil filter change )
According to the 2000 Ford Ranger Owner Guide : The ( 2.5 liter , 4 cylinder ) takes : With engine oil filter change ( 4.5 quarts / 4.3 liters of engine oil ) ---------------------------------------------------------------------------------------------- Also , the 2.3 liter DOHC , 4 cylinder in the ( 2001 ) Ford Ranger takes ( 4 quarts / 3.8 liters of engine oil ) with filter change
According to the 2001 Ford Ranger Owner Guide : With engine oil filter change : The 2.3 liter four cylinder engine takes ( 3.8 liters / 4.0 U.S. quarts of 5W-20 ) The 3.0 liter V6 engine takes ( 4.3 liters / 4.5 U.S. quarts of 5W-20 ) The 4.0 liter V6 engine takes ( 4.7 liters / 5.0 U.S. quarts of 5W-30 )
5 quarts ( 4.7 liters ) with filter change
With engine oil filter change ( 4.0 quarts / 3.8 liters of engine oil ) for the 2.3 liter four cylinder in a 2007 Ford Ranger
According to the 2010 Ford Ranger Owner Guide : With engine oil filter change : The 2.3 liter four cylinder engine takes ( 3.8 liters / 4.0 U.S. quarts of 5W-20 ) The 4.0 liter V6 engine takes ( 4.7 liters / 5.0 U.S. quarts of 5W-30 )
According to the 1997 Ford Ranger Owner Guide : The 2.3 liter / 140 cubic inch four cylinder takes : With engine oil filter change ( 5.0 quarts / 4.7 liters of engine oil )
According to the 1999 Ford Ranger Owner Guide : With engine oil filter change : The 2.5 liter four cylinder engine takes 4.3 liters / 4.5 U.S. quarts of (5W-30 engine oil )
With engine oil filter change ( 5.0 quarts / 4.7 liters of engine oil ) according to the 2001 Ford Ranger Owner Guide for the 4.0 liter V6 engine
According to the 2000 Ford Ranger Owner Guide : With engine oil filter change : The 2.5 liter four cylinder engine takes ( 4.3 liters / 4.5 U.S. quarts of 5W-30 )