You might try bleeding the sytem of air by removing the radiator cap when cool. then turning the heat temperature all the way to hot, then let the car run until it reaches operating temperature and then top off coolant in radiator and reserbiour.
If that does not help I am giving you a walk through diagnostic for your situation. Just use the link below tio get to it;

http://www.2carpros.com/articles/car-heater-not-working

Answered by DrCranknWrench (expert)
3,292 answers provided