Chevy van antifreeze leak inside van

Hey guys i have 91 chevy g20 with a 5.7L automatic, i was driving today and all of a sudden i smelled antifreeze i looked under the hood nothing i noticed on the passanger side there is antifreeze leaking from under a small black box any ideas on what the heck the problem might be.

best guess is the heater core has spung a leak. isolate the heater core and have a presure check done to prove the leak.

do you know a way to remove the heater core on a 91 chevy g20??

here is a basic start for you link:http://www.autozone.com/az/cds/en_us/0900823d/80/04/f4/ad/0900823d8004f4ad/repairInfoPages.htm