The owner's manual for the 2002 Mercury Cougar called for SAE 5W-20 premium-grade synthetic blend engine oil, a change over the previously recommended SAE 5W-30. Starting in January of 2002, however, Ford announced that all Mercury Cougars from 1993 through 2002 should use SAE 5W-20 engine oil with no substitutions for extreme cold climates. Pick a premium-grade synthetic blend with the API-certification stamp on the bottle.
If your Cougar has a manual transmission, use a full-synthetic manual transmission fluid. For the automatic transmission, transaxle and powering steering, use Mercon-V ATF fluid. The owner's manual called for Mercon fluid and warned against substituting or mixing with Mercon-V, however, in service bulletins released in 2006 and 2007 -- TSB 06-14-4 and TSB 07-1-7, respectively -- Ford announced that all applications calling for Mercon fluid should use Mercon-V fluid.
Replace the coolant in your Cougar with the same color coolant it came with. Motorcraft makes green, yellow and orange coolants. Your 2002 Cougar takes Motorcraft Specialty Orange Engine Coolant VC-2 or another extended-life coolant that meets specification WSS-M97B44-P. Don't mix coolant colors. The hydraulic brake system takes DOT3 fluid, but you can use DOT4 fluid in a pinch.
