Cabin Air Filters
Cabin air filters come in most factory vehicles these days. They clean the outside air from dust, pollen, and other airborne debris before it enters the evaporator and heater cores. Many contain charcoal filters that freshen incoming air and eliminate musty odors that form in humid conditions.
They’re secured in a tray found behind the glove box or under the cowl by the firewall. Depending on the manufacturer, they’re replaced every 10,000 to 15,000 miles or once a year. Be careful when removing the tray because the filter’s usually cluttered with leaves and filth that can spill onto the vehicle’s interior.
Cabin air filters can get dirty fast, depending on the driving conditions. Driving on dusty and gravel roads, wear the filter sooner. Parking a vehicle under the wrong tree quickly results in a filter like the one in the illustration. A clogged filter restricts airflow and allows dirt into the system. They can be expensive and are sometimes overlooked or left unchecked. If there’s little outside airflow with the fan set on high, suspect a clogged cabin air filter.