Mine did this too. I tried to think of every other possible thing wrong, but when it come down to it, the waterpump was bad. Find a NAPA store and have them order a DURAPRO pump for you. This one has the metal impeller. It is not hard to put in. I did mine myself and everything went smooth.

Blaze

1996 Sport LX Desert Violet Pearl(purple) 2.5 liter V-6 Name:(Grape) Finally Fixed