Q: heater on 1990 Oldsmobile 98

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
my heater blows but doesnt get hot.
(2) Answers
Check to see that rad is topped up,might need a thermostat,are there any fluid leaks,if so the rad will not hold pressure and wont make as much heat,did it just all of the sudden stop working or what?