According to the 2003 Mercury Grand Marquis Owner Guide :
With engine oil filter change
( 6.0 quarts / 5.7 liters of engine oil )
( 6 quarts with engine oil filter change ) according to the 2003 Mercury Grand Marquis Owner Guide
6 quarts will put it right on the mark.
According to the 2006 Mercury Grand Marquis Owner Guide : With engine oil filter change : ( 6.0 U.S. quarts / 5.7 litres of 5W-20 engine oil )
According to the 2003 Mercury Grand Marquis Owner Guide : With engine oil filter change : The 4.6 liter V8 engine takes : ( 5.7 liters / 6.0 U.S. quarts of 5W-20 )
According to the 1997 Mercury Grand Marquis owners manual : With engine oil filter change : ( 5.0 U.S. quarts / 4.7 litres of engine oil )
According to the 1997 Mercury Grand Marquis Owner Guide : With engine oil filter change : ( 5.0 U.S. quarts / 4.7 litres of 5W-30 engine oil )
( 6 quarts / 5.7 liters ) with engine oil filter change , according to the Owner Guide
With engine oil filter change ( 6 quarts / 5.7 liters ) according to the Owner Guide
According to my Chilton's Auto Repair manual : For a 1989 Mercury Grand Marquis : With engine oil filter change : Both the 5.0 / 302 and the 5.8 / 351 take ( 5.0 U.S. quarts )
According to the 2008 Mercury Grand Marquis Owner Guide : With engine oil filter change : The 4.6 liter V8 engine takes ( 6.0 U.S. quarts / 5.7 liters of 5W-20 )
The 2003 Mercury Grand Marquis Owner Guide shows ( 6 quarts with engine oil filter change ) for the 4.6 liter V8 engine
According to the 1996 Mercury Grand Marquis Owner Guide ( 5W-30 is the PREFERRED engine oil )