Toyota Repair: Exhaust/Collant leak, coolant level, head gasket

Question
I have a 96 toyota tacoma 2.7l 4 cyl. 4x4 with 265,000.
Recently I have noticed My coolant level going down, and white smoke coming out of the exhaust.  I checked the engine oil to see if the head gasket was leaking and nothing.  the other day I put some seafoam in the pcv valve to clean it and when I started it I not only had massive amounts of smoke coming from the tail pipe but also some coming from the exhaust manifold under the heat shield.  So I know that is cracked but where could the coolant be disapearing to?  Any help would be greatly appreciated.  Thanks in advance!!!

Answer
I'm fairly sure that there is a headgasket problem, it may have failed because of an overheating condition, these engines also are known to crack cylinder heads when overheated, the cylinder head should be removed for inspection of the headgasket and a possible cracked head.