twool

hey everyone, Quick question-- i have a 1999 subaru outback legacy 2.5L, that i changed the thermastat on about a week ago secondary to overheating. It fixed the problem until today, when the temp guage pegged out to hot. i have plenty of fliud in the radiator and no leaks in the system. Does this sound like the thermastat is bad again? The heat also only blows cold air when i turned it on to maybe try to cool down the engine.