1998 Saturn SL1 • 4 cylinder FWD • 90,000 miles

I have a 1998 saturn sl that keeps blowing cold air when I have the heat on. I did put in a thermostat last winter but not sure if I have the same problem.
December 19, 2010.

Check the coolant level, thermostat, heater core, heater control valve if it has one and the air blend door/actuator

Dec 19, 2010.
There is no heater valve on those make sure both both heater hose's going into the heater core are getting hot. If they are then I would be checking the blend door like rasmataz suggested. The arm for that is on the drivers side behind the heater control slider. Move the slider for temp back and fourth and watch the arm move for the blend door.

Dec 19, 2010.