I have a little experience with Ford vans. More with wives (wife, only one,
so far). My wife might report a wisp of vapor as a "massive cloud". No, not
might, she would.

Just some things to think about...

Is she seing exhaust blowing under the car and out the front? Assuming the
wind is from behind the car.

Could it be a damp engine heating up?

Is there coolant on the driveway?

Is the coolant level ok?

Somebody asked if it overheated. You might point out the gauge to her and have
her watch it.

Better yet, drive the van for a week or two yourself and see what happens.

Let us know what (if anything) you find. I'm curious.

Tom

Not my doing, Jeff, it's the wife. I will make no attempt to explain her
actions, I just pick up the pieces.

Thanks again everyone, never considered the fan or sensors. Will try that
next.

Why are you letting the van idle so long? It's really not good for the
engine.

On 2 occasions, my wife reported a massive cloud of steam coming from under
the front of the fan, both time after a cold start-up and idle of approx 15
min to an hour. It appeared (I was unable to see this happen myself, and
wife's description was less than helpful) that it may have "boiled over" and
ejected the coolant through the reservoir, running down over the exhaust
pipe.

What could cause this? One suggestion was a sticking thermostat, any other
ideas or confirmations? I really can't afford a trip to the garage for trial
and error, and I can change a thermostat myself.

Thank you all...