Ok, so my Bonneville will run at 200 degrees consistently, but have no heat. Air comes out, just not cold. Then magically, sometimes, the air turns hot. Car takes forever to warm up when cold and forever to cool down after driven. When the heat doesnt work, the coolant lines were a little warm and then I raced the engine a few times and the lines warmed up a lot and the heat started working. Thermostat is new, maybe the water pump? The car isn't overheating though? Possibly a bad rad cap? Opinions are welcome, Thanks!