The K&N 33-2374 is a panel-style, reusable replacement filter built on the brand's layered, oiled cotton-gauze media, which K&N says is engineered to improve airflow while still capturing contaminants. K&N washable, reusable High-Flow Air Filters feature a state-of-the-art design of layered, oiled cotton media engineered to improve airflow and capture contaminants. Its footprint of about 12.25 x 5.25 x 1.125 inches is sized to sit in the factory airbox of a 2.5L Altima instead of requiring any housing changes.
Against a disposable paper element, the appeal is long-term value. K&N describes the filter as lasting for the life of the vehicle and backs it with a No-Hassle Lifetime Limited Warranty. The manufacturer rates it at up to 99% filtration efficiency, and re-oiling calls for about 0.97 oz (29 ml) of K&N filter oil. K&N presents the design as a way to add horsepower, but no specific gain is confirmed, so treat that as a design goal rather than a measured figure. Buyers searching for a reusable 2.5L Altima drop-in filter, a cotton gauze airbox replacement, or a K&N 33-2374 upgrade are looking at the right part.
The manufacturer's listing covers the 2007-2012 Nissan Altima with the L4-2.5L engine, and this is the fitment to confirm first. Some third-party catalogs extend coverage to 2013 and to other models, so check your VIN against K&N's application data before ordering. Because it is a direct replacement, no modifications are needed. The job is a basic airbox service: remove the intake tube, open the airbox, swap the filter, and reassemble.
The manufacturer lists fitment for the 2007-2012 Altima with the 2.5L L4 engine. Some catalogs show 2013 applications, but the manufacturer's listing does not include them, so confirm your VIN with K&N before buying.
Per the manufacturer's installation sheet, the filter is a direct replacement for the stock filter and requires no modifications, but the sheet's sealing steps must be followed exactly.
The manufacturer specifies a re-oiling amount of 0.97 oz (29 ml) of K&N filter oil.
Per the manufacturer's installation sheet, this is a beginner-friendly airbox job with no modifications. Start by removing the two screws holding the stock intake tube, then unlatch the two clips at the top of the airbox and lift off the airbox base. Pull the stock filter, seat the K&N so its two tabs rest against the matching tabs in the airbox, then reinstall the base, relatch the clips, and refasten the intake tube. The sheet's sealing steps must be followed every time the filter is serviced, because a poor seal can let unfiltered air reach the engine. The sheet does not list specific tools, so basic hand tools should be enough, but check the fasteners before starting.
