5w 20
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The above answer of 5W-20 is correct if it is a 2001 or 2002 model year
according to the Mercury Cougar Owner Guides
( 1996 , 1997 , 1999 , 2000 guides show 5W-30 from the factory )
5w30
premium engine oil
If it is a V6 about 6 Quarts with a new oil filter.
On a 1991 Mercury Cougar : The oil pump is INSIDE the oil pan ( the oil pan is bolted to the bottom of the engine )
For a Mercury Cougar , 2.5 litre V6 engine : According to the 1999 to 2002 Owner Guides : ( Motorcraft FL-820 engine oil filter )
It came from the factory with ( 5W-30 )
Use Super Premium SAE 5W-20
According to the 1999 Mercury Cougar Owner Guide : ( 5W-30 ) is used in the 2.0 litre four cylinder engine and the 2.5 litre V6
5w 30
near the oil filter
The Owner Guide for the 1999 Mercury Cougar shows ( 5.8 quarts with filter change ) for the 2.5 liter V6 engine
with your eyes