This also depends greatly on the type of engine.........my '97 f-150
x-cab is on it's second 4.2 v-6 engine. It suffered major damage to the
motor upon startup at about 85,000 miles due to the well documented
coolant cover gasket failure and recall/repair failure. Amazing how a
problem can be as common as this one and FoMoCo does nothing about
it..........