There are two air filters in a 2018 Mazda 3: the engine air filter located in the engine bay on the passenger side, and the cabin air filter located behind the glove box on the passenger side. Both protect the car’s air intake and interior air quality.
Engine air filter location
The engine air filter sits inside a rectangular housing in the engine bay, toward the passenger side and connected to the intake hose that leads to the throttle body. Access is gained by unfastening the clips or screws on the housing lid.
- Open the hood and locate the engine air intake box on the passenger side of the engine bay.
- Unclip or unscrew the housing lid; Mazda models typically use a few plastic clips or small screws.
- Lift the lid and remove the old air filter, noting the correct orientation (the filter usually has an arrow indicating airflow direction).
- Wipe out the inside of the box if you see debris, then insert a new filter in the same orientation.
- Re-seal the lid and secure the clips or screws firmly; reconnect any hoses if you disconnected them.
Concluding: After replacing the engine air filter, start the engine to ensure it runs smoothly and check that the seal is tight. Typical replacement intervals range from about 15,000 to 30,000 miles depending on driving conditions.
Cabin air filter location
The cabin air filter sits behind the glove box on the passenger side. Access involves lowering or removing the glove box to expose a rectangular filter housing that is secured with a few screws or clips.
- Open the glove box and release the stops or pins so the box can hang down.
- Locate the cabin filter cover behind the glove box and remove the screws or unclip the cover.
- Take out the old cabin filter and inspect the housing for debris.
- Install the new cabin filter with the arrows indicating the direction of airflow toward the interior of the car.
- Replace the cover and reassemble the glove box, ensuring the stops engage properly.
Concluding: Replacing the cabin filter improves interior air quality and HVAC efficiency. Mazda generally suggests checking or replacing the cabin filter every 15,000–25,000 miles, with more frequent changes in dusty conditions or if occupants have allergies.
What to know and tips
Notes: There can be minor variations by trim level or production batch. If you’re unsure, consult the owner’s manual for exact steps and the recommended service intervals. Basic tools (a small screwdriver or a trim tool) can help with clips, and use the correct filter size specified for your vehicle.
Summary: For the 2018 Mazda 3, the two air filters live in distinct places: the engine air filter in the engine bay on the passenger side, and the cabin air filter behind the glove box. Both are straightforward DIY tasks that, when done regularly, help maintain engine performance and interior air quality.