otep could be right, it could be the evaporator dahil humina ang lamig....

with regards to your question about a 4 year old car needing aircon work, yes, it is possible. my Lancer 2k had a major aircon overhaul dahil nasira yung expansion valve and evaporator last year (2003), which means 3 year old pa lang yung car and just travelled around 30 thousand kms.