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It's (Not) Complicated (Engine Air Filter)

July 6, 2025

While many components of your vehicle are complex and composed of lots of mechanical and electrical parts, there's one that isn't complicated but still important.  It's your engine air filter.

(And, we should point out, the engine air filter isn't to be confused with the cabin air filter.  The cabin air filter cleans air that goes into the passenger compartment while the engine air filter cleans air that goes into the engine itself.)

Why does your engine need a filter? Think of all the stuff–dirt, dust, and debris in the air¬–that gets kicked up on the road.  If that were to go unfiltered into your engine, it could damage other components.

There are many different materials used in an engine air filter, including paper, cloth (frequently cotton), and other synthetic fabrics.  The material is usually folded tightly to maximize the filtering capability over a relatively small surface.  

Before computers were employed to determine the proper mix of air and gasoline, a dirty air filter could contribute to a decline in fuel economy.  But a study of engine air filters done by the U.S. Department of Energy in 2009 found that in modern fuel-injected engines, computers can maintain the correct air/fuel mix even when an engine air filter is really dirty, minimizing effects on fuel economy.

That same clogged air filter, though, can affect your vehicle's performance, mainly how much power and acceleration it delivers.  In testing three different vehicles, a dirty air filter made the vehicles slower by about 6-12%.  That's something you'd definitely notice if you were driving.

But it happens slowly, over the course of several months, so you might not even know your engine air filter is dirty unless you bring it to us and have a technician inspect yours.  

There are many different types of engine air filters, from the ones made by the original vehicle manufacturer to aftermarket ones.  Some can increase your engine's performance; some can be washed and re-used but are generally more expensive.

Your service advisor can recommend several options for you, depending on the type of vehicle you drive and your driving habits.  Dirty, dusty roads will require more frequent engine air filter changes than cleaner drive routes, and each vehicle manufacturer recommends when your filter should be changed.  Keeping it clean will help your engine breathe a little bit easier.

Tuffy Bloomington
1505 East Vernon Avenue
Bloomington, Illinois 61701
309.662.0537

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