Sounds like either head gasket, cracked head or cracked block
Remove both upper and lower radiator hoses and run your garden hose water through from the top opening.
On a 2001 Mercury Cougar : The radiator is located in the engine compartment , at the front of the vehicle
Remove radiator cap. Push Cougar out of the way. Push a better car under the radiator cap. Install radiator cap.
SLIDE OFF THE LOWER RADIATOR HOSE AT THE RADIATOR...
The power for the radiator fan comes through the fuse, the sensor, and the relay. The location of lost power could be at any of these places.
The radiator fluid is low or you parked the car at am angle.
The radiator on a 1999 Mercury Cougar is flushed by draining the radiator, filling it with water, and adding a commercially available radiator flush. The engine is allowed to circulate for 10 minutes, drained, flushed with fresh water, and refilled with coolant.
No, it has no cap on radiator. You fill radiator thru the reservoir cap on the rt side of engine. Hope this helps.
the radiator itself is either aluminum or copper only the tanks are plastic
No , the thread on cap on the engine coolant reservoir is the pressure cap / radiator cap
it is filled in the overflow tank. the cougar has a sealed system and there is no radiator cap like typical cares
If this is a '99 through '02 Cougar, this sounds like the so called "Moosing" problem, which is a problem with the Idle Air Control Valve (IACV), and is fixed by taking the IACV out, its connected to the upper intake manifold, and either cleaning it thoroughly, or replacing it.