My 1990 honda prelude is running hot!!!!?

This head gasket is the seal between the coolant and your hot combustion chamber. Once that gasket is worn, the coolant will be sucked in to the combustion chamber and the engine will also overheat. The coolant in the combustion chamber will cause the engine to run rough. As the coolant exits the combustion chamber, it comes out the tail pipe as sweet smelling white smoke.