i had a leak in the plug that holds the tube and seal in place.
i had to replace the dex cool every week or so cuz they couldn't get the part in in a timely fashion.
if you get it repaired, make sure its a reputable shop that will warranty the work. i personally will never go to an independent shop again, long story...
and remember, its dex cool, not anti-freeze.
you put antifreeze in there and you're gonna have some problems.