BMW Repair: 325i bmw 1994 sedan., 325i bmw, head gasket

Question
hi,josh mi bmw was overheating and I do change the thermostat. so after that the engine start smoking very bad and I can see like coolant or water is coming out front the mufler pipe.so I really dont know what it is.and what is you best recomendation about it,thanks.

Answer
Francisco,
 This sounds very bad.  If the engine overheats it will warp parts of the motor.  When these parts warp they allow coolant and oil to leak; sometimes even into the cylinders so they will be burned.  Hopefully it's just a blown headgasket, but it could be worse.
 I would pull the head off the engine and look at the head gasket.  You should notice a large hole or break in the gasket.

 Good luck,
 Josh