Ford Repair: Ford Explorer 1997 2wd (150k mi), blown head gasket, exhaust gas oxygen

Question
White smoke coming from exhaust.

Radiator and spark plugs were just replcaed due to leak and check engine light staying on.

What is the likely cause of the problem and how much should it cost to fix?

Thank you very much. I know this isn't much info. Anything you can offer before I take it to another shop and pour money in the thing will be appreciated.

Answer
The white smoke in the exhaust is steam, it means that water is being burned in the engine.  Some white smoke is normal, especially in cold weather.  Water is a by-product of condensation and combustion.  An excessive amount of white smoke from the exhaust, a loss of engine coolant, and a rough-running engine would indicate a blown head gasket, and/or a cracked cylinder head.  The check engine light could be on because the Exhaust Gas Oxygen (EGO) Sensors are contaminated with coolant.  If this is the problem with your vehicle, it is not an easy fix and could cost a couple thousand dollars for repairs.

I hope this helps,
Dave