Nissan Repair: 240sx, headgasket, antifreeze

Question
noticed small leak of antifreeze under car,a few days latter temp gauge maxed out(very hot).replaced thermostat but temp still goes high.while looking into radiator to see if antifreeze was circulating(with engine running) it seemed to erupt out of radiator. is it water pump thats bad?

Answer
Benny,

If you have a new thermostat and have burped the system of air and it is still doing the antifreeze blowing out of the radiator I would be checking the water pump to make sure it is circulating.  Also, check to see that the headgasket is intact and that the exhaust converter is not plugged.  I once did work on a 240SX adn replaced the headgasket just to find that the exhaust converter was plugged and that is what blew the headgasket in the first place.  The dealer had replaced her radiator thinking that would solve the overheating problem.  She did not make it another 30 miles before the headgasket blew from the exhaust restriction.