Coolant tube replacement

The plastic coolant tube on top of the radiator of 1st generation Foci is prone to failure. Fortunately, it's easy to replace.

The coolant tube can be acquired cheaply online or for less than $50 at your local dealership. I had a hard time finding the part at third-party stores like AutoZone, though.
First, pop out the plastic rivets holding the tube in place.
Next, use a pair of pliers to remove the hose clamps. Remove the hoses from the old, broken tube, and attach them in the same order on the replacement tube.
Re-install the hose clamps, then snap the rivets back in.
While doing this maintenance, it's probably a good time to check your entire cooling system. You'll need to refill your cooling system after performing this repair anyway. Take a look at the following articles for more information:

Cooling system bleed and refill

Replacing the thermostat (or thermostat housing)

Testing your thermostat