Why am I leaking water out of my resivour tank?

Help I finally got my new radiator and got it put in. The truck is no longer reading its getting hot but ive noticed that theres a little water coming from the resivour tanks over fill hose. What could be causing this? Could it be the thermastat has gone out on it? When the truck is warmed up to normal temp Ive sqeezed the house coming from the engine to the radiator but water just comes out of the resivour over fill hose. Thank you for all your guys help I greatly appreciate it. please get back to me asap.

Thank you
Jennifer