What Is An Air Filter, and What Does It Do?

Your vehicle's internal combustion engine requires air, fuel, and spark in specific quantities to generate power. The necessary air is drawn from outside the vehicle and passes through the air filter before entering the engine. Outside air, however, is filled with potential engine-damaging contaminants, including grains of sand, leaves, dirt, pollen, even bird feathers. The air filter's job-much like that of the fuel and the oil filter-is to trap these harmful contaminants and prevent them from being sucked into the engine where they can cause damage.

When Should You Replace Your Air Filter?

An air filter is a maintenance item that needs to be replaced regularly. Ideally, that's every 12,000 miles or 12 months-more often if the vehicle is driven regularly in a dusty environment. As contaminants build up in the air filter's paper or cotton barrier, it becomes increasingly difficult for air to flow through, which, in turn, can cause significant engine performance problems.

Warning Signs Your Air Filter May Be Dirty

Your vehicle's performance problems may all stem from a dirty or clogged air filter. Here are several warning signs to look for:

• Decreased engine power, throttle response, or acceleration
• Poor gas mileage
• Misfiring or rough-idling engine
• Gasoline smell
• Black smoke
• Check Engine light illuminated