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Your car has two air filters, and most people only know about one. Both cost only a little money. Both take about 10 minutes. And the dealer often charges 3 or 4 times more than they should to change them. If you have never fixed anything on a car before, this is the perfect place to start.
The Two Filters — What Each One Does
Engine Air Filter
This filter cleans the air that goes into the engine. Your engine needs clean air to burn gas and make power. If this filter is clogged, the engine cannot breathe well, and it can feel slow or lazy. It also keeps dirt from scratching the inside of the engine.
Cabin Air Filter
This filter cleans the air that comes into the car through the vents — the air you breathe. If it is clogged, your vents blow weak, the car smells musty, the windows fog up, and dust and pollen blow right in your face. This one has nothing to do with engine power. It is all about clean air for you.
Most people have never changed the cabin filter. If your car has 60,000 miles and you have never touched it, pull it out and look — it will be gross.
How Often to Change Them
| Filter | Normal Driving | Dusty or Dirty Air |
|---|---|---|
| Engine air filter | Every 15,000–30,000 miles | Every 12,000–15,000 miles |
| Cabin air filter | Every 15,000–25,000 miles | Every 10,000–12,000 miles |
Easy test: hold the filter up to a light. If light does not shine through, it is dirty and needs to be changed.
Part 1: Change the Engine Air Filter
What You Need
- The right new filter for your car
- A flathead screwdriver or a 10mm socket (depends on the car)
- A rag or a small vacuum
The Steps
- Find the airbox. It is the big black plastic box in the engine area with a fat tube coming out of it.
- Open the box. On the Civic and Accord, flip up the metal spring clips by hand. On the Camry and RAV4, it is clips and sometimes a couple of 10mm bolts. On the F-150, clips hold the lid and it lifts from the front.
- Take a photo of the old filter first. Notice which way it sits. There is usually an arrow or a flat edge that must face a certain way.
- Lift out the old filter and clean the box. Vacuum or wipe out any leaves and dirt in the bottom. Do not let it fall toward the engine.
- Put the new filter in the same way the old one was. The rubber edge must sit flat all the way around so no dirty air sneaks past.
- Close the lid and snap every clip shut. A loose lid can cause a whistle or a rough idle.
Part 2: Change the Cabin Air Filter
This one scares people because it hides behind the glovebox. But on almost all of these cars, you need no tools at all.
The Steps (Civic, Accord, Camry, RAV4)
- Empty the glovebox. You are about to drop it down.
- Let the glovebox swing all the way down. Gently squeeze the sides inward so the little stop tabs slip past the dashboard. Now it drops lower than normal. Some cars also have a small arm on the side that unclips.
- Find the plastic cover. Behind the glovebox you will see a flat rectangular cover. Pinch the tabs and pull it off.
- Slide out the old filter. Get ready — it will be full of leaves, dust, and maybe bugs. Do this outside if you can.
- Check the arrow on the new filter. It almost always points down on these cars. Putting it in upside down blocks airflow.
- Slide the new filter in, put the cover back, and lift the glovebox back into place. Make sure the stop tabs click back in.
Ford F-150 Note
The F-150 is different. On many of them the cabin filter is under the plastic panel at the bottom of the windshield on the passenger side, not behind the glovebox. Some years did not even come with one. Check your exact year before you buy the part.
Cost: Do It Yourself vs the Dealer
| Service | DIY Cost | Dealer / Shop |
|---|---|---|
| Engine air filter | $15–$30 | $50–$90 |
| Cabin air filter | $12–$30 | $60–$110 |
| Both together | $30–$60 | $110–$200 |
About 20 minutes of your time saves over a hundred dollars. This is the best deal in all of car care.
Should You Buy a Fancy Reusable Filter?
Some people buy oiled reusable filters. Be honest about what you get: on a normal engine, they do not add power you can feel. Worse, too much oil on them can dirty an important sensor and cause problems. For a daily-driven Civic, Camry, or F-150, a good paper filter is the smart pick. It is cheaper, filters better, and needs no care.
Signs You Waited Too Long
- Weak air from the vents even on full blast — cabin filter
- Musty or moldy smell when the AC turns on — cabin filter
- Windows fog up and will not clear — cabin filter
- Engine feels slow when you press the gas hard — engine filter
- A whistle from the engine — engine filter or a loose airbox lid
Make It a Habit
Change your filters when you change your oil. Every other oil change, pop open the airbox and hold the engine filter to the light. Once a year, pull the cabin filter. It takes minutes, costs almost nothing, and helps your car live to 200,000 miles.