Mercury 1997 Cougar Manual page 214

The coolant additives also protect the entire
cooling system from internal passageway
corrosion and these additives lubricate the water
pump. The coolant should be serviced as noted
in the Maintenance Schedule booklet.
The engine coolant reservoir
Checking Hoses
Inspect all engine and heater system hoses and
hose connections for deterioration, leaks, and
loose hose clamps as specified in the Maintenance
Schedule booklet. Repair or replace with
Motorcraft hoses or equivalent as necessary.
214