According to the 2012 Ford Mustang Owner Guide :
With engine oil filter change :
The 3.7 liter V6 engine takes :
( 6.0 U.S. quarts of 5W-20 )
The 1998 Ford Mustang owners manual shows ( 5 quarts ) WITH FILTER CHANGE
With engine oil filter change : V6 / 5 quarts V8 / 6 quarts According to the 2008 Ford Mustang Owner Guide
The 2007 Ford Mustang V8 takes 6 quarts of oil
The 3.8 liter V6 engine in a 2003 Ford Mustang takes ( 5 quarts ) WITH ENGINE OIL FILTER CHANGE
( 6 quarts ) with engine oil filter change on your 4.6 L - 2006 Ford Mustang
It should take 5 quarts of 5W-30
The 1996 Ford Mustang owners manual shows : WITH FILTER CHANGE 3.8 L - V6 engine - ( 5 quarts ) 4.6 L - V8 engine - ( 6 quarts )
My Chilton repair manual shows ( 5 quarts - U.S. ) WITH FILTER CHANGE for the 302 V8 engine in a 1976 Ford Mustang II
I believe that is almost 3 quarts
5 quarts ( 4.7 liters ) WITH FILTER CHANGE for the 4.0 L - SOHC - V6 engine in a 2008 Ford Mustang
A 2001 Ford Mustang 3.8 liter V6 engine takes ( 5 quarts ) with engine oil filter change ( according to the Owner Guide )
( 5 quarts ) with filter change - according to the 2000 Ford Mustang owners manual