It’s summer time, you are headed to the store. It is 95 degrees outside, you get in the car and crank up the AC. You are pulling out of your driveway, it is faint at first but then you get the full musty, sweaty sock smell that comes from the vents. You hold your breath and quickly turn the vents away from your face. Knowing it will soon go away. Slowly the smell goes away and all is well…. Until you come out of the store and do it all over again. Ok so maybe it isn’t that bad but most of you have experienced that smell before. That smell is coming from wet debris that is collected on the ac evaporator. The evaporator is located behind the dash and is how you get cold air out your dash vents. The debris is dust and small particles of leaves and other things from the air wherever you live. They make their way down the cowling through the fresh air duct and get stuck on the evaporator. The evaporator collects moisture while it does its job. The debris then gets wet and will start to form mildew. That is the source of that annoying smell.
The best way to get rid of that debris and smell is to remove and clean or replace the evaporator. That can be very time consuming and costly depending on your make and model of vehicle. I allow my evaporator to dry before I shut my car off. 5 or so minutes before I shut off my car, I turn the AC off but leave the fan on high. This allows the evaporator to dry thus minimizing the mildew build up on the surface of the evaporator. Furthermore, replacing your cabin air filter (if your vehicle has one) is another way to make sure the air from your vehicle vents is clean and smell free. If the smell in your car is not very bad yet. There are some products out there that can coat the evaporator to neutralize the mildew and mask the odors.