Try seeing if the rubber gasket has frayed or bubbled around any part of the door. This is a common [http://ezfixappliancerepairlasvegas.com/brands/frigidaire-appliance-repair-las-vegas/|Frigidaire Refrigerator Repair] especially, for older units or fridges kept outdoors (like mine at home in the garage).
Just my 2 cents...
-Fred
Repair Tech
[http://www.ezfixappliancerepairlasvegas.com/|Las Vegas Appliance Repair Expert]