Posted on 9/26/2025
If your car’s air conditioning fills the cabin with a musty or sour odor, there’s a good chance something is happening behind the dashboard that you can’t see. Many drivers first notice this smell after turning on the A/C following a period of hot or humid weather. Even though it may fade after a few minutes, it’s not something you should ignore. A persistent odor can point to underlying issues with moisture, mold, or air circulation inside the HVAC system. Understanding the common causes behind these smells can help you prevent future problems and keep your car’s cabin air fresh and clean. Why the A/C Smells in the First Place When your vehicle’s air conditioning is running, it cools the air by drawing heat out of it using a component called the evaporator coil. This process naturally creates condensation. In a properly functioning system, that moisture drains away through a small outlet underneath the car. But in real-world driv ... read more