'98 Subaru: My heater is blowing cold air!?

[contretemps]

My 1998 Subaru Impreza Outback is not heating up like it used to. I parked it at the airport during the holidays and now, three weeks later, when driving home, I discovered that the heater is blowing cold air. The first 45 minutes of the drive it was fine, but the last hour or so it was blowing cool air.

About 2 months ago I noticed that the thermostat gauge near my speedometer never moves; the needle is stuck below COLD. I don't know if that has anything to do with my heat problem or not.

Anyone have any ideas on either of these issues?

 

[CameronN]

I have a 98 subaru mine does that when it is low on water. When I add it it blows hot. After I changed the water pump I never had to put water in it again. It colud be a clogged Readiaateor I would get it flushed

 

[LieutenantMauro]

Get your thermostat replaced. It's most likely stuck open and keeping your motor to cool to do anything with heat. Or if it's stuck mid way it's only going to partially work. 9 times out of ten though if your thermostat gauge ain't working it's the actual thermoastat on the motor.