Crusader fresh water coolant leak

[snuffysteve]

For the second season in a row my '93 crusader 350 lx leaked about a quart or so of antifreeze from the fresh water cooling side into the bilge during winter layup. Last season I just refilled the coolant and ran the boat all summer long without having to add another drop. I cant seem to figure this out. Also all the coolant is gone from the small overflow tank. Im sure the coolant didnt freeze over the winter...it checks to -50 and the temp didnt get much below 20 degrees all winter. Any suggestions would be appreciated.