Actually... I noticed the same problem with my 97 3.1 lumi and it was coming from the 'lil rubber hose that attaches the 2 sections of heater pipe right above the waterpump... that damn thing was leaking so little that i didnt notice it til I did the pump, but the hose was wet and a slight wetness at the top of the pump housing by the 2 bolts... just my

... ofcourse if it isn't that... all the other suggestions are worth a good checking... considering the advice Ive gotten here has saved alot of $$$, heartburn and swearing... not to mention time too...
MYX