Cck date field save not working properly

I am saving a date field and when i print the value as
print_r($node->mydate[0]['value']);
it is printing only year value (2012). When i check the content by editing it it shows me 1st of January 2013 in date field. This problem is only for one field. If i adds a new date type field with same setting in same content type that works perfectly. Please help. I checked all actions and in my custom code but still not found anything wrong with that. If i update timestamp value with my sql query using db_query that still have problem. I can't delete my field because of my previous content.