Either the thermostat is stuck shut of the water pump is bad. Make sure that the coolant is full as well, then check the thermostat and pump to see why the coolant isn't flowing.
Check the 1991 Legacy for a stuck thermostat. Check to make sure that the water pump is working properly.
One reason is engine overheating - check your temp gauge and coolant as a first step.
Probably a bad thermostat.
55 degrees to 60 degrees
faulty control valve on heater or air in the lines
The coil is dirty.Hose it out with a water hose.
Coolant level is probably low, Have it checked for an antifreeze leak.
sounds like the head gasket ...same thing just happened in my 97 cavalier
most likely thermostat stuck less than $ 15 part
Low coolant?Bad thermostat?System airbound?Bad water pump?
There are 2 filters you access in the glove box. If they are dirty you get almost no air. Clean or replace them and be amazed at the difference
There should be at least a 12 degree split between the incomming air and the air comming out of the vents.