"93 Caravan

The auto: 93 Dodge Caravan
the scenario: large billowing clouds of white smoking from the exhaust
the mechanic on the phone: "sounds like major trouble"
...I have to wait til tomorrow to hobble it up there....
question: How bad does it sound? What could it be? estimated cost...Thanks!

Sounds like coolant is getting into your engine. The means that you may just have something as simple as a blown head gasket to a cracked block and/or head. Head gaskets aren't very expensive but new blocks or heads are VERY expensive. Did you overheat the car at all? If so, how bad? How many miles is on your engine? Also what engine is it?

The engine is a 3 L. I have not overheated it....it has about 150,000 miles on it.

Interesting. . . .

My guess would be a blown head gasket. I am sure you haven't been driving it? If so, don't. I would take it in and have them look at it, but that would be my guess.