BMW Repair: 2000 323i overheated, blown head gasket, coolant tank

Question
i bought a 2000 323i, the guy i bought it from says it overheated and crystalized the head, what does the mean?. so i brought it home and now looking at it and cant figure it out. the coolant tank has this thick thick muck and its this creme color. i checked the oil dip stick and it fine clean oil. the car sounds good when started. how would i be able to figure this out? how would i clean out the muck?

Answer
Tim, the muck is motor oil that has mixed with coolant from either a Blown head gasket (Best case), a cracked cylinder head (not so good), or a cracked engine block (worst). So you need to figure out what has failed to mix the two fluids together. None of the fixes are cheap. If you take the cylinder head off to replace the head gasket then release and retorque the head bolts to factory torque to make sure the aluminum threads in the block will hold once you put the motor back together
-Evan