According to my Chilton's Auto Repair Manual :
With engine oil filter change :
( 5.0 US. quarts for all factory available engine sizes )
According to the 2001 Mercury Cougar Owner Guide : For the 2.0 litre four cylinder engine : ( with engine oil filter change , 4.25 litres / 4.5 U.S. quarts of 5W-20 engine oil )
I'm assuming it is the same as the ( 1996 ) Mercury Cougar 4.6 liter V8 : With engine oil filter change : ( 5.0 U.S. quarts should put you almost to the full mark )
On a 1991 Mercury Cougar : The oil pump is INSIDE the oil pan ( the oil pan is bolted to the bottom of the engine )
According to the 2002 Mercury Cougar Owner Guide : The 2.5 liter V6 engine takes : With engine oil filter change : ( 5.5 litres / 5.8 US. quarts of 5W-20 engine oil )
The oil capacity should be with the filter 5.5 L ( 5.8 qts )Without filter 5.0 L( 5.3 qts ).
According to the Owner Guide : With engine oil filter change : 5.0 quarts ( 4.7 liters ) of engine oil
It takes alot. I just fill to 6 quarts. It always go right to the max. This is only if you are replacing the oil filter to though.
2.5 V6 5 liters without the oil filter.. 5,5 liters with the oil filter 2.0 similarly: 3.75 4.25 This data is from the genuine owners guide
5w30
5w 30
near the oil filter
with your eyes