Sounds like the Thermostat may be stuck in the open position. Hurry and replace because this condition will cause your water pump to fail shortly after. Cold air was my first sign and because I didn't replace it, I'm now replacing the thermostat, water pump, timing belt and balance shaft belt(because they got wet when the pump went out). $250.00 doing it myself, approximately $670.00 at the dealer.
I have an 03 Galant and when it started blowing cold air it was because of a defective cut off valve in the metal heater line just outside of the heater core. The design of the A/C and heater system places them together requiring that hot water not flow the heater is not in use. It is located next to the glove compartment and will require the removal of the dash pad.
I had a similar problem with Chevy Lumina when the thermostat went out. It was stuck open so the car never got up to a temp high enough to blow hot air. Kerry
Low refrigerant?
the most common cause of this is your engine coolant may be low. If this is the case then there is not enough of it to pump through your heater core (the coolant is hot from you engine, it is pumped though a serise of tube-like things similar to a radiator and then air is blown across it to make the air hot). That or your heater core itself may be broken in wich case it cost about 100-200 with labor to get a new one.
10 w30 is a good weight as long as it isn't to cold
newer galants have electrical speedometers,have had lots of success repairing them by removing and resoldering connections for COLD solder joints. REMEMBER to DISCONNECT BATTERY before you do this!
The front expansion valve is clogged.
it is not a thermostat problem is an actuator located under the dash that lets the water pass through the heater core, all these cars got the same problem dude good luck... Possible the thermostat installed upside down. Spring goes toward engine. Also may be air in the system. Bleed the cooling system with the heater set to hot. The heater core may also be stopped up.
Have your servo control checked
We just put a new cd player in my daughters car. we had it done professionally but now we have no heat coming out of our heater, just cold air. Do you think they did something wrong? Could it be the blend door
Most likely cause is low coolant. Check your antifreeze level.
Blows cold air through the heater. Overheats. Bubbles/oil in radiator. Check spark plugs for condensation on plug tips.
She was Sandra Brennan.