1998 MAZDA MILLENIA Engine And Engine Cooling Problems

I HAVE HAD A TERRIBLE TIME WITH MY 1998 MAZDA MILLENIA. WE BOUGHT THE CAR IN 2001 WITH APPROX. 30,000 MILES. IT SEEMED LIKE A GREAT CAR. THEN ONE DAY IT DIED AS I WAS TURNING INTO MY DRIVEWAY AT HOME. THANK GOODNESS I WASN'T DRIVING ON THE MAIN ROAD. IT WAS DIAGNOSED WITH A HEAD GASKET PROBLEM SHORTLY AT 70,000 MILES. WE IMMEDIATELY ATTEMPTED TO REPLACE THE GASKET. MY MECHANIC DISCOVERED, AFTER ENTERING THE ENGINE, THAT THERE WAS A CRACK IN THE BLOCK. SO WE REPLACED THE ENGINE WITH A USED ENGINE WITH 30,000 MILES ON IT. IT, TOO, HAD COOLANT IN THE OIL. THE THIRD ENGINE IS ALSO THE SAME. I SPOKE WITH A SERVICE AND PARTS MANAGER, JIM KELLEY, AT CENTURY MAZDA IN AUGUST 2003. HE KNEW THE PROBLEM RIGHT AWAY. SEVERAL MAZDA MILLENIAS MADE IN THAT YEAR HAD A "FAULTY WATERPUMP". HE SAID IT WASN'T RECALLED....