I have a coleman air purchased 7/2009 TCGD30s21s2A , have replaced the ac coil twice, last week was the second time. It was leaking freon, the freon is always gone by the second date, I need help

Are you absolutely, positively certain there isn't a leak ELSEWHERE in the system? And that its without any doubt actually leaking from there, confirmed with a leak detector?

Coleman - Warranty (http://www.coleman.com/warranty/)

The guy check with a leak detector and dye and the ac coil is the only think that showed up