What is a car engine air filter?

On the Road 3 min read

An engine air filter in your car filters out dirt, debris, and other particles that could harm the engine. An engine air filter’s purpose is to ensure only clean air enters a car’s engine. We talked to two car experts to learn how car engine air filters work and how to tell when they need to be changed. Max Turner is CEO of Car Donation Centers, and Jed Lehman runs the informative website Gearshift.co. Lehman says you can find engine air filters in an external component of the engine bay — in a black plastic box called an air box.

This houses your vehicle’s air intake and often sits above the engine. When you remove the airbox cover, your car’s engine air filter will be visible.

Signs your car engine air filter needs to be changed

According to our experts, these are the telltale signs that could mean it’s time to change your car’s engine air filter:

  • The filter looks dirty or clogged
  • The engine stalls frequently
  • The car accelerates slowly or doesn’t start right away
  • You notice black smoke coming from the exhaust pipe
  • Your vehicle hesitates while you’re driving
  • The car’s fuel economy has decreased
  • Your car’s check engine light has turned on

Note that these can be signs of an old engine air filter, but they may also indicate other problems. If your filter looks fine, but your check engine light is on, or something seems off with the engine, take your car to a mechanic to get their opinion.

How to change an engine air filter

Changing your car’s air filter is a straightforward process, even if you don’t have any mechanical experience. You may consult your manual for tips related to your specific car make and model, but according to our experts, the following steps apply to most vehicles.

Purchase a new air filter

You can find them at most car parts stores. Make sure you purchase a filter that’s a correct match for your car’s make and model, and year.

Locate your car’s airbox and remove the cover

Open the hood of your car and look for a small black box usually situated near the front. Undo any clamps or latches that are holding the airbox in place. Depending on your car, you may also need to unscrew some nuts and bolts.

Remove the old air filter and clean the airbox

Unlock any clips that are holding the air filter in place. Then you’ll be able to remove the air filter from the airbox piping. Lehman suggests using this time to clean the surrounding area, too, as dirt and grime can build up on the airbox piping. You can use a special cleaning formula or a simple mixture of water and grease-cutting dish soap.

Attach the new air filter and replace the cover

It should fit snugly into place. Turner recommends comparing your old and new filters before attaching the new one to be sure they match. If the filters look different, consult your car’s manual or a mechanic to ensure the new filter won’t cause any damage to the engine’s components. Once the new filter is in, lock it into position. Put the cover back and secure it with the latches or nuts and bolts.

How often to change the air filter in a car

An engine filter change is generally needed about every 15,000 miles. However, it may need changing more often if you drive in a dusty environment or an area with relatively high levels of air pollution. Consult your car’s manual and keep an eye out for the telltale signs mentioned above.

Keeping a regular maintenance schedule, following some basic car maintenance tips, and changing your air filter regularly will help your car last longer. Addressing mechanical issues swiftly will also improve your vehicle’s longevity.

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