1997 Saturn SL2 leaking fluid

My son called me last night with several engine light lighting up, I suspect either a broken belt based on the "noise" he described. The car was leaking engine coolant, when he tried to top it off with water, the water drained quickly. A friend said the leak appeared to be comming from the water resorvoir line, it looked like a copper line going to the firewall and down be the engine(!). I have been trying to locate a diagram of the cooling system on the net, but no luck. Any ideas what they maybe talking about, I am driving to the car this afternoon and have no idea what I am up against.
Thanks in advance.