Why Does the Car AC Blow Smelly Cold Air?
2 Answers
Foul odors from the car AC when blowing cold air may be caused by: 1. Dirty air conditioning ventilation ducts or a clogged cabin air filter. The cabin air filter should be replaced regularly, as an excessively dirty filter not only fails to function properly but also causes secondary pollution to the air entering the vehicle. To completely eliminate odors inside the car, it's essential to address the root cause. Under normal conditions, an OEM cabin air filter has a service life of one year or 30,000 kilometers. If the vehicle frequently operates in areas with poor air quality, the replacement interval should be shortened accordingly. 2. Long-term use of the AC evaporator can lead to mold growth due to moisture, resulting in unpleasant smells. Drivers should turn off the AC cooling 5 minutes before reaching their destination and switch to natural ventilation. This allows the temperature inside the AC ducts to return to normal before parking, preventing condensation due to temperature differences after turning off the engine. Keeping the AC ducts dry inhibits the growth of mold and fungi.
Having unpleasant odors when turning on the AC is a very common issue, mainly caused by mold and dust buildup in the air conditioning system. Take the evaporator for example - its surface temperature gets extremely low during cooling, causing moisture condensation that easily leads to mold growth. Remember to turn off the AC compressor a few minutes before parking, letting the fan run to dry out the moisture. Don't skimp on the cabin filter either - I usually replace mine every six months, otherwise trapped pollen and dust can ferment and stink inside. If the smell is really strong, get a professional deep cleaning at an auto shop where they spray disinfectant foam through the ducts and evaporator. After treatment, it'll feel fresh like a new car again.
