How to change the air filter in a car: A step-by-step guide for mechanics

You might think that changing a car’s air filter is no big deal, especially since this is something that DIYers try to do at home. Often enough, it’s the easy tasks, the ones we rush, that can go wrong. The filter, for instance, could be placed a little off-center, or maybe the seal gets pinched under the cover. The job is done, but the engine may now be drawing in unfiltered air. To make sure this doesn’t happen, here’s our step-by-step guide on how you should change the air filter in a car.

Why do cars even have air filters?

A car’s air filter keeps bugs, dust, sand, and other debris from getting into the engine. It helps protect the engine’s sensitive parts from damage. Most air filters are rectangular or square and made from a paper-like material that lets air through but blocks dirt.

Why should a car’s air filter be replaced regularly?

Reduces emission

A clogged air filter can block airflow and harm your car’s emission system. This can cause your car to release more harmful substances into the air. Changing the air filter regularly helps protect the environment.

Increases engine life

A clean air filter helps your engine last longer by keeping out dust and dirt. This prevents damage. Changing the air filter is an easy way to save money and keep your engine running smoothly for a long time.

Do dirty air filters impact fuel economy?

Customers often ask to replace a dirty air filter to improve fuel economy. But is there solid proof that changing a dirty air filter helps fuel economy in modern cars?

Oak Ridge National Laboratory tested cars from the 2000s and found that a clogged filter didn’t make much of a difference to fuel economy, since the engine computer adjusts to the air it gets. Those cars lost acceleration instead, and DOE has reported 6 to 11 percent better acceleration on average with a clean filter.

Older carbureted engines are the exception, and they did burn more fuel when the filter clogged.

The truth you can tell a customer who’s asking is that a clogged filter makes the car feel sluggish. The engine risk comes from a filter that leaks or is missing, because dust gets into the cylinders.

How often should you replace a car’s air filter?

If someone asks, the usual advice is to change the air filter every 12,000 to 15,000 miles. If you drive often or in dusty areas, you may need to change it sooner. Remember to include air filter changes in your regular engine care. Here’s what the top 5 car brands in the USA recommend.

Brand	Replace at	Source
Toyota	30,000 miles	KBB Toyota schedule
Ford	30,000 miles	KBB Ford schedule
Chevrolet	45,000 miles or 4 years	KBB Chevrolet schedule, 2016 Equinox manual
Honda	15,000 miles in dusty conditions	Honda Maintenance Minder PDF
Hyundai	30,000 miles or 24 months	Sonata schedule

Signs that a car’s air filter needs to be replaced

• A clean filter is usually white or off-white. A clogged filter, on the other hand, looks dark gray, brown, or black and blocks light if you hold it up to a bulb.
• The acceleration can turn sluggish, or you might feel like the power has reduced. This happens because there’s less air going into the engine.
• You might notice rough idling or sputtering because restricted airflow can disrupt combustion and may even trigger the check engine light
• If you smell gasoline or see black smoke, these are signs that the engine is running too rich because of poor air intake.

How to change the air filter in a car in 7 easy steps

1. Check what type of filter is needed using the car’s VIN or the owner’s manual before opening anything. Two filters may look the same but can differ by a centimeter, and that small difference can cause a seal to fail. If your shop is using Way Repair Tech, order the filter from the repair order so the part number matches the car on your lift.
2. Open the hood, locate the airbox, and release the clips. Some airboxes use screws instead, so check before you try to open it.
3. Lift the old filter out in one steady motion so loose dirt doesn’t fall into the intake duct.
4. Check the air filter pleats for packed dirt, oil, tears, or other damage. You can also hold the filter up to a work light, but don’t rely only on this test, as it may not always be accurate.
5. Wipe the airbox with a soft cloth or use a vacuum. We recommend that you avoid brushes that stir up dust. While you’re cleaning, keep an eye out for leaves, nests, or oil.
6. Place the new filter in the same position as the old one, making sure the rubber edge is sealed all the way around.
7. Close the cover, fasten it, and gently pull to make sure it is secure. If the manufacturer provides a torque specification for the cover, follow it.