Check your hoses and hose clamps that go into the heater core outside the firewall and make sure they are in good condition befor you go moving them around too much. While moving them around inside the car, I cracked one close to the clamp, but that just means that they needed to be changed anyway, but the movement finished them off. It's just something else you might want to check after you get everything back together. I don't know if it's recommended to disconnect them first, or not, but I never did. I also fogot to connect one of the temperature sensors, and wound up with hot air blowing at the same time the A/C was on, so make sure you connect everything back. You might want to take some pictures too. This helped show me how everything was connected before.