I have a 1990 subaru legacy ls. has about 155k miles on it. starting a few months ago it would overheat while driving farther than about 5 miles from my house usually on the way back but i would go up and come right back down. now it will overheat and blow cold air with heat on high to those places 5 miles or more. the waterpump was replaced about two years ago(2008). the radiator was replaced in july of 2009,just put a new thermostat in it. My dad has bled it many times to get any air out but it doesnt seem to work at all. everyone says is not a blown headgasket but all signs kinda point to that. Also what we noticed when it does begin to over heat when we hit the gas it will go up higher when we hit the brake it goes down. Any ideas???