The Altima uses a standard rectangular panel engine air filter in the engine air intake box; the exact filter depends on whether your car has the 2.5-liter four-cylinder (QR25DE) or the 3.5-liter V6 (VQ35DE), and part numbers vary by market. The cabin air filter is a separate component with its own replacement.
This article breaks down the engine air filter options for the 2009 Altima, explains how to identify which engine you have, and covers the cabin air filter and routine maintenance considerations.
Engine air filter: 2.5L vs 3.5L
Both engines in the 2009 Altima use a standard panel-type engine air filter housed in a rectangular air box. The filter is a single-paper element designed to be replaced as a unit. Exact part numbers and fit can vary by engine and market, so verify the part with your VIN or owner’s manual.
- 2.5L four-cylinder QR25DE: Engine uses a rectangular panel air filter in the engine air intake box. The filter is a single-panel element; ensure the replacement matches the housing opening for the QR25DE.
- 3.5L V6 VQ35DE: Engine uses a similar rectangular panel air filter within its own intake box; though the form is the same family, the exact size/fit differs from the 2.5L.
In practice, both 2009 Altima engines use the same general panel-filter concept, but you should confirm the correct filter by engine code (QR25DE vs. VQ35DE) or by matching the existing filter or OEM cross-reference.
How to identify your engine
Check the engine code stamped on the engine itself or consult the vehicle identification number (VIN). The 2.5L QR25DE code is used for the four-cylinder variant, while the 3.5L VQ35DE code is used for the V6 variant. If in doubt, refer to the owner's manual or contact a Nissan dealer with your VIN for the precise replacement part.
Cabin air filter
Separate from the engine air filter, the cabin air filter cleans air entering the climate control system. On many 2009 Altima models, it sits behind the glove box and is a standard rectangular panel or cartridge-style filter depending on the market.
- Location and access: typically behind the glove box; you may need to lower the glove box and detach a cover to reach the filter.
- Form factor: cabin filters vary by market and may be a rectangular panel or cartridge; ensure you select the correct type for your vehicle.
Regular replacement, typically every 12,000–15,000 miles (or once a year in moderate climates), helps maintain HVAC performance and interior air quality. Check your manual or the dealer for exact intervals and part numbers.
Summary
For a 2009 Nissan Altima, you need a standard panel-type engine air filter for either the 2.5L QR25DE or the 3.5L VQ35DE. The exact part number and fit vary by engine and market, so verify using your VIN or the official parts catalog. Don’t forget the cabin air filter, which is a separate replacement item located behind the glove box, and should be changed on a similar schedule to keep interior air clean. When buying replacements, rely on OEM cross-references or reputable aftermarket brands and confirm fit before purchase.