White smoke from the exhaust is normally a sign that the water from the cooling system is being fed into the combustion chambers and coming out of the exhaust as steam The white smoke.
The cause of this could well be a head gasket failure. If the engine has got very hot then it may have started to burn up the engine oil.
I suggest you check engine oil and water in radiator. If one or both below level investigate further, compression check or contact a garage
Maurice, March 2011
