I have a guess but its pretty bad news, I work fro firestone and recently threw 4 waterpumps at a 96 duratec, until we found the headgasket was leaking and allowing pressure to build up int he waterpump and bam it blew
which would show signs of blowing first a big mean headgasket or a wimpy paper waterpump gasket... I hope this isnt your case but it is surely a possibility

Derek Johnson 88 TurboTBird 32psi, t3/t4 bb 50trim, megasquirt, 3 bar map, 50lb inj, roller cam w adj. gear, header, 3" downpipe and full exhaust, gutted intake manifolds, spec stg 3 95SE 3L gone