Ford has all owners manuals online for free, so you can easily check if you no longer have one, but should be 5. I have had Rangers with the same engine and they were all 5. You can fill filter, install, put 3 in the engine and wait for it to drain down, then top off slowly allowing time to reach bottom of eng until right level, start (to pressurize filter) wait for drain and then check again but I would stil buy 5 qt container since it's cheaper than buying the qts individually. If lower miles(below 80) switch to synth-it will extend eng life.
The 2005 Ford Taurus's engine produces 185 ft-lbs. @ 3950 rpm.
The 2010 Ford Taurus's engine produces 249 ft-lbs. @ 4500 rpm.
The 2013 Ford Taurus's engine produces 254 ft-lbs. @ 4000 rpm.
The 2002 Ford Taurus's engine produces 185 ft-lbs. @ 3950 rpm.
The 2011 Ford Taurus's engine produces 249 ft-lbs. @ 4500 rpm.
The 2001 Ford Taurus's engine produces 185 ft-lbs. @ 3950 rpm.
The 2004 Ford Taurus's engine produces 185 ft-lbs. @ 3900 rpm.
The 2012 Ford Taurus's engine produces 249 ft-lbs. @ 4500 rpm.
The 2003 Ford Taurus's engine produces 185 ft-lbs. @ 3950 rpm.
The 2007 Ford Taurus's engine produces 185 ft-lbs. @ 3950 rpm.
The 2008 Ford Taurus's engine produces 245 ft-lbs. @ 4500 rpm.
The 2014 Ford Taurus's engine produces 254 ft-lbs. @ 4000 rpm.