Car Talk Service Advice: Air Filters

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Modern air filters are cylindrical or rectangular like this one from a Ford Explorer.
Modern air filters are cylindrical or rectangular like this one from a Ford Explorer.

What is it?

The air filter stops airborne contaminants from getting sucked into your car's engine. It's a paper filter that stops debris such as dust, leaves and wayward pelicans before they get inside the engine and do damage.

Should I do this service when it's recommended?


Why do I have to do this?

Because, eventually, your air filter will get plugged up.

What happens if I don't do this?

If your air filter gets too dirty or clogged, your engine won't be able to suck enough air into the combustion chambers. The engine will then run rich (i.e., too much gas and not enough air). When this happens, your car will lose power and run roughly. Your Check Engine light also may come on.

If you really neglect the air filter for a long time, your car may stop running altogether. While permanent damage is unlikely, it is possible. If an air filter were sufficiently dirty and damaged, it could allow harmful, abrasive contaminants into the combustion chamber.

Can I Do This Myself?

It depends on where you rank on the Car Talk do-it-yourself scale:

There are two kinds of screwdrivers?
I've successfully hung pictures around the house.
I've changed my own oil.
I've fixed things on my car that involve removing more than five bolts.
I've built a working nuclear reactor out of wood.

Is there any maintenance required between intervals?

If you operate your car under severe duty, such as frequent driving on dirt roads or a lot of stop-and-go driving around town, then you should halve the recommended service intervals for the inspection and replacement of the air filter.

Car Talk Tip: Inspecting and replacing your air filter is an easy task. Almost anyone can do it ... with the possible exception of Jerry Springer. By purchasing the filter directly from an auto parts store, you can sometimes save $10 or more, in addition to the labor costs.

photograph by Joe Wiesenfelder,

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