Nissan Repair: nissan overheating, nissan altima, vacuum line

Question
my nissan altima is overheating i,ve replaced the head gasket and somehow managed to keep it in time, anyways i thought it was poor coolant circulation so i replaced the thermostat and the waterpump also i have messed with the water control valve near the thermostat and that seemed to help but it still runs a little hot.I was also thinking that it might be some sort of vacuum line or sensor that i overlooked but i checked all of those and the problem seemed to be somewhere else. so do you have any suggestions?

Answer
Thomas,

Be sure the radiator is clean and I would go so far as to have it cored out.  Replace the cap and make sure the fans kick in when they should.  I have seen things as simple as the fans not working causing all kinds of problems.  You can check the fans by turning on the airconditioner and if they come on the motors are good.  If not hot wire and check each of them.  Now, with the car running make sure the fan comes on when the car is at temperature.  If not replace the temperature sensor that controls the fan.