Something funny about my heater

Well, actually its not funny at all. I searched the other threads and didn't really come up with anything that sounds like what i have. My 95 sunfire is having problems with the heat it produces. See, i turn it on and its blowing warm air. Not very warm, but warm enough to thaw the windshield. After running for maybe 10-15 minutes, it stops with the warm air and starts blowing cold air. I live in a small town and the mechanics aren't especially honest, so i want to rectify this problem myself. Any help would be awesome and thanks in advance.

Sounds to me like a bad thermostat or you are low on coolant.

check your coolant line before and after thermostat if your temp arn't the same before and after thermostat after car has been ruuning for awhile sound like thermostat...what is you temp gauge reading after you car runs for awhile...and check to see if there are any air pocket in your coolant sysstem you can let the car run for awhile with the car off and this should clear all air pockets good luck

sorry with cap of coolant tank