Had to change the rad in my 99 Caravan. It started to leak where the tube of the core meet the end plate. The fluid was changed every 5 years or longer. My experience has been that ever since they got away from the old copper/brass radiators, they just don't seem to corrode. I cut it open to see what it looked like inside. Most of the time, the fluid used was a cheap old green style glycol mix. As of late I couldn't find that fluid so I used a universal type. Clean as a whistle.