Air Filters

The engine air filter decides how much abrasive dust reaches the cylinders and turbocharger. In dry, unpaved or construction environments it is often the most important service item for engine life, and it is replaced much more frequently than on vehicles in clean urban conditions.

Types

• Panel filters – flat, rectangular elements with a molded polyurethane or rubber frame. Common on passenger cars, SUVs and many pickups.
• Round (cylindrical) elements – used on trucks and some older pickups, with end caps sealing axially.
• Radial-seal elements – seal on the inner or outer diameter rather than the end face, typical of newer truck air cleaners.
• Primary and safety (inner) elements – two-stage truck systems use a primary element that is serviced regularly and a secondary element that protects the engine during primary service.
• Pre-cleaners and cyclonic housings – remove heavier dust before the filter.

Quality points

The filter frame and seal matter as much as the media. A poorly molded seal lets dust bypass the pleats entirely. Pleat count, pleat depth and spacing affect dust holding capacity and airflow restriction. Some elements use a flame-retardant media treatment or a wire mesh support to prevent pleat collapse under high airflow.

Applications

Pickups such as the Ford Ranger and Toyota Hilux are frequently used on dirt roads and in mining or agriculture. For those users, pair air filters with snorkels and pre-cleaner options. Truck air cleaner elements are covered in truck and bus filters.