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On most cars you replace a cabin air filter by opening the glove box, releasing it so it drops down, pulling the old filter out of its housing, and sliding a new one in with the airflow arrow pointing the right way. There’s usually nothing to it beyond finding the right filter and being careful with a few plastic clips.
This filter cleans the air coming through your vents. It has nothing to do with the engine air filter under the hood, so make sure you’re buying the right part.
- Time: Usually a short job once you’ve found the filter.
- Difficulty: Easy on most cars. Some models bury the filter deeper, and that’s where it stops being easy.
What you need
- A new cabin air filter that matches your exact year, make and model
- Your owner’s manual
- A flashlight
- A small vacuum or crevice tool to clear the housing (vacuum options)
- A trash bag, because old filters shed leaves and dirt
- Basic hand tools, only if your manual says the job needs them
If you still need a filter, you can search cabin air filters here. Confirm the fit for your exact vehicle before you buy. Some add activated carbon aimed at odors, so check whether your manual specifies a type.
How often to change it
Your owner’s manual has the answer, listed in its maintenance schedule. Intervals vary by vehicle, and the right timing also depends on how and where you drive, so that schedule beats any general rule you’ve heard.
Between services, these are signs it’s time to look at the filter:
- Weak airflow from the vents, even on a high fan setting
- A musty smell when the fan runs
- A filter that’s visibly dark and packed with debris when you check it
A smell doesn’t always mean the filter’s the cause, though. See the section on when to get help below.
How to replace it
Safety first. Switch the vehicle off before you begin. The Ram owner’s manual warns not to remove the filter while the vehicle is running, or with the ignition in the accessory or on position. With the filter out and the blower running, the blower can contact your hands and can throw dirt and debris into your eyes.
- Look up where yours is. The filter usually sits behind the glove box, but your manual has the exact location and access steps. If your car doesn’t follow that pattern, go by the manual.
- Empty the glove box. Take everything out so nothing falls on the floor.
- Release the glove box. Many glove boxes drop down once you press in on the sides or disengage a small stop. Some have a tension tether or damper that needs unclipping first. Go gently and follow your manual, because these plastic tabs can snap.
- Remove the filter cover. This is usually a thin plastic door with tabs on the ends. Press the tabs and pull it off.
- Note how the old filter sits. Look for an arrow on its edge, and take a photo before it comes out. It’s the easiest way to get the new one in the same way around.
- Slide the old filter straight out. Keep it level so debris stays on it and doesn’t fall into the housing. Bag it right away.
- Clean out the housing. Vacuum up any leaves and dirt you can reach. Don’t spray cleaner or water in there. Liquids and the electrical parts behind the dash don’t mix.
- Install the new filter with the arrow pointing the right way. The arrow shows airflow direction through the filter. Which way that is depends on your car. In the Ram 2500 and 3500, for example, the arrow points toward the floor. Your manual or the marking on the housing will tell you. Some filters are marked differently, such as “top” or “up.”
- Close it up. Press the cover on until it clicks into place on both ends. Ram’s manual calls for an audible click, and that’s a good test for any car.
- Refit the glove box. Reattach any tether or stop, swing it up, and check that it opens and closes properly.
- Test it. Start the car, run the fan through its settings, and check that the air flows strongly and nothing rattles.
Common mistakes
- Getting the arrow backwards. The Ram manual warns that a badly installed filter will need replacing more often. Check the direction before you close the cover.
- Buying by guesswork. Filters look alike, but a filter that’s slightly the wrong size can leave gaps. Match it to your exact vehicle.
- Forcing the glove box. If it won’t release, you’ve missed a stop, tether or screw. Check the manual again.
- Working with the ignition on. Leave the car off until the cover is back on.
- Leaving the cover loose. A cover that hasn’t clicked in can rattle or let unfiltered air past.
- Spraying the old filter with air freshener. That covers up a smell without solving it. Replace the filter.
When to hire a pro
Most people can do this one themselves. Have a shop do it if your manual shows that access means removing trim or parts you aren’t comfortable with, or if the filter housing has broken clips.
See a mechanic if you’ve fitted a new filter and the airflow is still weak, or if the fan makes noise. That points to a problem elsewhere in the heating and air conditioning system.
If the airflow’s fine and the cabin still smells, the source may not be the filter at all. Start with these ways to get rid of car smells, and give the dash and vents a proper clean. Add the filter to your car care checklist so you don’t lose track of it.
If the smell has settled into the interior itself, find a detailer near you to treat it.