Low coolant? Bad thermostat? Heater core airbound, plugged or restricted? Water pump not circulating coolant?
why does my 2002 chevy cavalier over heat after i change the thermostat and the water pump
thermostat
Check your coolant level.
Muffler Heat Sheild
Heater Airbound? Heater control cable not working? Heater core plugged?
heat not working
try looking at your resistor pack on the passsenger side lower the blower motor down and there is a heat coil and resistor in there
Exhaust components rust out over time due to weather and the heat from the vehicle. On a 2001 Chevy Cavalier, when the muffler strap rusts, welding a new strap in its place will offer a complete and reliable repair.
I'd check the coolant level first, then the thermostat.
check cabin filter
Thermostate stuck closed or low on anti-freeze or pluged heater core or bad water pump or the the A.C to heat deverter valve (if equipt) not operating correctly
need to install rear heat to my Chevy astro it already have rear air condition