Engine Air Filter and Cabin Air Filter
The engine air filter prevents abrasive particles from entering the intake system and scoring cylinder walls and pistons. Most modern engines use a flat-panel or cylindrical paper element housed in a plastic airbox. Replacement interval is typically 15,000–30,000 miles or annually, but varies greatly by driving environment — dusty, unpaved roads require more frequent replacement. Inspection is visual: hold the filter up to a light source. A white or light gray filter is serviceable. A dark gray filter with visible dirt loading in every pleating fold should be replaced. A black or deeply contaminated filter significantly restricts airflow, leaning out the fuel mixture and reducing power. Replacement requires only unclipping the airbox lid (usually 2–4 clips or bolts), noting the filter orientation, and swapping the element — a 5-minute task. The cabin air filter serves the HVAC system, filtering outside air entering the passenger compartment. Located behind the glove box or under the dashboard, it catches pollen, dust, and debris. Replacement interval: 15,000–25,000 miles. A clogged cabin filter reduces HVAC airflow significantly — often mistaken for a failing blower motor — and can harbor mold that produces musty odors. Cabin filter replacement takes 5–10 minutes and filters are inexpensive ($15–$30).