On top of the radiator. If there isn't an 'obvious' cap, then there really isn't a conventional type cap. Topping off the cooling system is done through the coolant resevoir. When I emptied the system on my daughter's 2002, I pulled the lower radiator hose and then refilled the radiator through a funnel into the very small upper radiator hose, and then topped off the resevoir. That seemed to have covered it as I have not had to add any more since then.
On a 2001 Ford Focus : The thread on cap on your engine coolant reservoir is the pressure cap / radiator cap
On a 2002 Ford Explorer : The thread on cap on your engine coolant reservoir is the pressure cap / radiator cap
On a 2002 Ford Explorer the thread on cap on the engine coolant reservoir is the pressure cap / radiator cap
On a 2002 Ford Escape : The thread on cap on the engine coolant reservoir is the pressure cap / radiator cap
On a 2002 Ford Explorer : The thread on cap on the engine coolant reservoir is the pressure cap / radiator cap
On a 2002 Ford Expedition : The thread on cap on the engine coolant reservoir is the pressure cap / radiator cap
The thread on cap on your engine coolant reservoir is the pressure cap / radiator cap
There is one but underneath the frame on the radiator.
Push DOWN hard, and turn to the left. They have a security lock.
For a 2002 Ford Taurus : The thread on cap on the engine coolant reservoir is the pressure cap / radiator cap ( I believe the Motorcraft part number is RS-103 ) it's a 16 PSI cap
Does not have one. Just a reservoir.
On the overflow bottle. It's the only one.