why no heat on 2003 Chevrolet Astro

core hoses not hot , new radiator and coolent

3 answers
change your engine block thermostat. its not a big job, I change my own. wont cost a lot to have repaired.
ck coolant level to start with then make sure you don't have any blockages. could be a fresh air door issue or a number of other issues
core hoses not hot = blockage somewhere...