Is it a front wheel drive?

If so, they are notorious for the splines failing on the water pump and power steering pump. The camshaft has a pulley at the back of the head which drives a belt. This belt drives the PAS pump and the water pump is splined to the back of it so is driven by the PAS pump. The splines wear out and the water pump loses drive.

The cure is a new water pump AND power steering pump as they both lose their splines at the same time. Ford have a surcharge on the pumps so they want the old units back after they have been changed...