The air filter for a 2008 Honda Civic sits inside a rectangular plastic air box in the engine bay and is replaced by swapping in a new filter. The box connects to the throttle body with a large intake hose and is typically found on the driver’s side of the engine compartment. This guide covers common LX/EX models and notes minor variations for the Si trim.
Where to look in the engine bay
In most 2008 Civics (such as LX and EX with the 1.8-liter engine), the air box is located on the driver’s side of the engine bay, near the front or along the fender. The housing is a rectangular black plastic component with a thick hose feeding into the throttle body. The Si variant uses the same general arrangement, though the intake routing and mounting points may differ slightly due to the higher-performance engine.
What you’ll see is a sturdy plastic box with a removable lid, secured by clips or small screws. Inside sits the flat, rectangular air filter, oriented to allow air to flow from the intake hose into the engine.
Replacement steps
If you're preparing to replace the air filter, follow these steps:
- Park on level ground and let the engine cool. Open the hood and locate the air filter housing on the driver’s side of the engine bay.
- Unclip or remove the fasteners holding the housing lid. Depending on the model, you may have metal clips, plastic fasteners, or small screws.
- Lift the lid and carefully remove the old air filter. Note how it sits in the housing so you can install the replacement the same way.
- Inspect the filter; if it’s dark, dusty, or torn, replace it with a new filter of the correct specification (OEM or equivalent).
- Check the orientation of the new filter and align the filter’s airflow direction with the markings in the housing if present.
- Install the new filter, reseat the housing gasket, and reattach the lid with the fasteners. Ensure there are no gaps that could let unfiltered air in.
- Reconnect any hoses or clamps you moved, start the engine, and listen for unusual air leaks or misfires. A quick test run confirms a proper seal.
In short, locate the driver’s-side air box, open the lid, replace the filter with the correct orientation, and reseal the box. A typical replacement interval is about 30,000 miles under normal driving conditions, with more frequent checks in dusty or harsh environments.
Summary
The air filter on a 2008 Honda Civic is housed in a rectangular air box in the engine bay, usually on the driver’s side. Replacement involves removing the lid, swapping in a new filter, and reassembling, paying attention to the airflow orientation. Follow the recommended maintenance schedule—about every 30,000 miles under normal conditions—and inspect the filter more often in dusty conditions to maintain engine performance and fuel efficiency.