What the engine air filter does
The engine air filter stops dust and debris from getting into the engine with the air it burns. It sits in a plastic box under the hood. It’s a different part from the cabin air filter, which cleans the air you breathe — the two usually have different intervals.
Signs it needs replacing
- The filter looks dark and clogged when held up to light
- Leaves, debris or signs of animals in the air box
- Slightly sluggish acceleration
On modern fuel-injected engines, a dirty filter mostly costs a little power rather than much fuel economy. It still needs replacing on schedule to keep dirt out of the engine.
Checking and changing it yourself
- Find the air box — usually a black plastic box connected to a large hose leading to the engine.
- Release the clips or screws and lift the cover.
- Lift out the filter and check it. Note which way it sits.
- Wipe out any debris, fit the new filter the same way, and close the box securely so it seals.
Buy the filter listed for your exact engine. Record the date and mileage so you know when it was last done.
Common questions
Can I clean a paper air filter?
Standard paper filters are meant to be replaced, not cleaned. Washable filters exist but need the correct cleaning and oiling.
Do performance air filters help?
For an everyday car, rarely in any noticeable way. A standard filter that matches your manufacturer’s specification is the safe choice.