I'm having troubles getting heat out of the Liberty. I believe the blend door is working fine as I can get temperature variation from cold to hot, but when I have it on hot and run the fan up its hardly any heat at all. This to me points to the heater core. I've tried back flushing, but it makes no difference. I have great flow through the heater core when flushing in forward or reverse, what I'm wondering is that if the passageways in the heater core are plugged would the water come through at all? Is there a built in bypass of some sorts, or does the water have to go in one side and out the other? I want to research all options before I go through the task of changing it. Speaking of changing it, does anyone have a step by step, or manual for doing it?