Why Does the Car AC Smell Bad When Starting?

[DanteRose]

An unpleasant odor when first turning on the car's air conditioning may be caused by mold growth on the AC evaporator, where bacteria accumulate and multiply. Additionally, not replacing the cabin air filter for an extended period can also lead to foul smells when the AC is turned on. To address this issue, it is recommended to install a new cabin air filter or thoroughly clean the existing one before reinstalling it. Reasons for AC odors include: 1. Evaporator: The evaporator is the primary component responsible for AC cooling. During the cooling process, it comes into contact with external air, particularly in heavily polluted urban or industrial areas, which can draw contaminants and dust into the AC circulation system. While most particles are expelled during routine cleaning, some residue remains and can eventually produce odors over time. 2. Cabin Air Filter: The main function of the cabin air filter is to purify incoming air. Over prolonged use, it can accumulate dirt and debris. If left uncleaned or unreplaced for too long, it may develop a foul smell.