Your engine uses about as much air as it does fuel, and the air filter keeps dust and grit out of it. A clean filter protects engine parts and keeps airflow free. This guide compares the main filter types and explains when to replace them.
Engine air filter and cabin air filter
The engine air filter cleans the air going into the engine. The cabin air filter cleans the air coming through the vents into the cabin. They are separate parts with separate replacement intervals, so check both.
Types of engine air filter
- Paper (cellulose): the standard replacement. Inexpensive, good filtration and disposable.
- Oiled cotton gauze: reusable performance filters, such as K&N. They flow more air and can be washed and re-oiled, but they need correct maintenance: too much oil can coat a mass airflow sensor.
- Dry synthetic: reusable filters that need no oil, such as some aFe Power designs, with easy cleaning.
When to replace or clean it
Many makers suggest checking the engine filter at every oil change and replacing it every 12,000 to 15,000 miles, or sooner in dusty places. Hold it up to the light: if you cannot see light through it, it is time. Signs of a clogged filter include reduced power, poor fuel economy and a rough idle. Cabin filters are typically replaced every 12 months or 15,000 miles, or when airflow from the vents drops or a musty smell appears.
Do performance filters and intakes add power?
A less restrictive filter or a cold air intake can improve throttle response and sound, and gains in power are usually modest on a stock engine. They work best as part of a set of upgrades. Our comparison of K&N vs aFe Power intakes explains how to choose, and our guide to cleaning a performance filter shows how to maintain one.
Common questions
Does a dirty air filter hurt fuel economy?
A badly clogged filter can reduce power and economy, especially on older engines. On modern fuel-injected engines the effect is smaller, but the filter still protects the engine.
Can I clean a paper filter?
No. Paper filters are disposable. Only filters designed to be washed, such as oiled cotton or dry synthetic types, can be cleaned and reused.
Where to buy
Shop air and fuel delivery parts including filters and intakes. We are an authorized dealer for every brand we sell, shipping is free anywhere in the USA, and returns are accepted within 60 days (unused, in the original packaging) and return shipping is free. Not sure what fits your vehicle? Contact our support team and we will help you check before you order.