white smoke

I have a '92 Grand AM (quad 4) and a problem just occured. When I start the car it shuts down in about a second, when I start it again it does'nt shut down but white smog comes out the tail pipe. A friend said that it could be that I have a water leek and it's getting into the fuel engine which could damage the heads, is this true?

Considerable white smoke is usually indicative of blown head gasket