hi i recently had a leak in my radiator so i used rad weld which was fine the problem now is that the temperature keeps going up after driving for a while so turn the heater on full and that brings the temp back to normal. The actual water is still at the wright level in the plastic water chamber.Please help

 

There are many possible causes of overheating. The radiator could be plugged internally or externally. The water pump could be bad, the fan(s) could have a problem, the thermostat could be bad, the antifreeze could be bad, the head gasket could be leaking, etc., etc, etc.
Somebody knowledgeable is going to need to take a good look, maybe run some tests.