If it is a V6 about 6 Quarts with a new oil filter.
It will take a skilled mechanic approximately 5 hours to change the fuel pump in your 1991 Mercury Cougar. It can take a novice mechanic much longer.
follow the raditor hose it will have to bolts look for the bolts take them off and it inside the hose.
a 95 mercuy cougar takes anywhere from 5 to 7 quarts of transmission fluid
5w 20 ======================================================== 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
take to dealership. there was a recall and they will fix it for free.
If it is a 1999 or 2000 Cougar, then it'll take a while, many professional shops have trouble doing it in less than 8 hours, prepare to take longer than two days if you do it yourself. If you have the slightly redesigned 2001 or 2002 Cougar, it is much easier, as the mounting bolts are easier to get to through the fender wall. There are instructions for the job, no matter the year, at newcougar.org.
R-12
take the terminals off the battery and run a wire brush through them, or sandpaper.
Take it to theglass repair guy
passenger side bottom back of the engine. to get at it you need to lift the car, remove the front passenger wheel, and take off the splash guards
The 2001 Mercury Cougar does not contain Freon. Freon was banned in 1996. I suggest you take this vehicle to someone who has the knowledge, tools, and skill, to repair the A/C system.