Im pretty sure I have a head gasket issue so I have to fill my coolant on the regular but even when it has coolant on max heat it still on puts out tepid air. I need to flush out the heater core as yesterday my thermostat froze causing my heater hose to burst, so I figured I'd do that before I put on new hoses. I just need my car to last a few more months until I can park her for a proper rebuild.