i changed the coolant today and now think i have a problem. i drained the coolant with the car cold. i refilled with a bottle of the bars leak stuff (not the pellets, the other bars leak) and a 50/50 dexcool. now when i run the car it gets to the notch past half way before the thermostat opens and it cools down. (i know the stat is opening bec the lower hose gets hot wheras it was cool before) problem is before the new coolant the needle never got past half way at all. what gives? did i miss something? HELP!!