If this is the hose that goes down after it exits the water pump in a funny "S" shape, then I think you should know that my dealer diagnosed this as leaking on my 2.3, but what actually was happening was the water pump was leaking sending the fluid down the outside of this pipe making it look like the pipe was leaking. The engine heat would dry up the antifreeze around the pump so it looked clean there.
Your water pump could be the problem. My car did heat up fast with the bad water pump. But try and clean the pipe and see if you can detect a hole in it. How about placing a rag around the pipe to help in the detection. BE CAREFUL OF THE FAN!!!!
Hope this helps......