heater blowing luke warm air, blows strong just not hot on 1997 Chevrolet Camaro

heater blowes strong but no hot air. I hear the door opening and closing

Asked by for the 1997 Chevrolet Camaro
2 answers
Thermostat may need to be replaced. Heater core 'itself' may be restricted and needs flushing.
CK COOLANT LEVEL 1ST BEFORE STARTING ANY REPAIRS. IF COOLANT IS LOW CK FOR LEAKS