Paul,
I think thats the overflow hose that drains to the ground. I would certainly replace the coolant tank and refill with the type specified for your coolant system, See lable on tank.
Bill
Bill & Kathy Francis
95 Itasca Sunrise 29RQ,P32 454 Chevy, Banks,ECM chip.Safe-T-Plus, Bilsteins, Super Steer Bell Crank, Stewart Stage 1 Waterpump, Severe Duty Fan Clutch, OilGuard Bypass Filter, Coolant Filter. Rear Tracbar. 1-5/8" Front Swaybar.