How can I fix my 2000 Ford Tarus Se?

The water reservor cracked did not overheat,replaced reservor and about month later it started overflowing, replaced cap, had a new reservor installed last month,heater was blowing cold air, new cap at same time. The temp gauge did go up but not in the red. During all this constantly filling reservor,now that has stopped but resvor is too full. Oil is clean not milkie, can do 70 on interstate no problem, no smoke. Any Ideas help would be nice. This is a 2000 Ford Tarus Se Wagon with 153000 miles. Thanks RC