How do I get the coolant system over flow tank off?

It is not terribly difficult but the lower hose can be. I recently had to remove mine because it started to leak.By the way, this isn't your typical overflow container. It is actually part of the cooling system. You are going to remove a few bolts and a hose on top and underneath. I had to remove the battery to be able to get my hand under it to get the short hose back on.I cut mine while taking it off out of frustration and put a new one on during re-installation. Be sure to put both clamps on the lower hose after connecting it to the metal line(tighten this one)and before bringing the container completely into position. You will have to bring one hand underneath as your putting it into position to connect the hose to the container. You'll be glad the clamp is already on the hose when your one hand wrestling this line on. All because of the a.c condenser which is right in the way throughout the whole process. I didn't remove it because I didn't want to go through the headache of recharging the a.c system either. Take your time and you'll be fine. Good luck.