The K&N 33-2009 is a panel-style replacement engine air filter built on the brand's oiled cotton gauze media, designed to drop into the factory airbox in place of a disposable paper element. The manufacturer says it is designed for high airflow while maintaining filtration levels critical to ensure long engine life. Its main purchase case over stock paper is reusability: the element can be cleaned and reoiled rather than replaced at every service, which offsets the higher upfront price over the life of the truck or van.
Fitment is where buyers should slow down. The manufacturer lists the filter for Toyota 4 Runner, Toyota Cressida, Toyota Masterace, Toyota Pickup, Toyota Spacia, and Toyota Van models, but year ranges differ across sources, so confirm your exact model year, engine, and airbox layout before ordering. For installation, the manufacturer's sheets for its panel filters generally call for removing the airbox lid, pulling the stock element, wiping out debris, seating the K&N, and pressing around the edges to confirm a seal. Search terms this filter matches include 33-2009 washable air filter, reusable Toyota 4Runner air filter, and 1985-1989 4Runner 2.4L intake filter.
The manufacturer lists the 4Runner, Cressida, Masterace, Pickup, Spacia, and Van. Its application page shows a 1985-1989 4Runner with the 2.4L four-cylinder. Year ranges vary between sources, so confirm your exact year, engine, and drivetrain with the manufacturer before ordering.
The manufacturer's product page says the element needs cleaning about every 75,000 miles under normal highway driving. Another manufacturer overview gives up to 50,000 miles depending on conditions. Details vary, so check with the manufacturer for your use case.
The manufacturer states the filter is emissions legal in all 50 US states and will not void the vehicle warranty.
Installation is a basic airbox job, not an engine modification. Expect to open the airbox lid (some models use clamps or screws), remove the stock element, and wipe out any dirt in the housing before seating the K&N. Make sure the filter sits fully and the edges press evenly against the airbox so the lid closes without gaps. Cleaning and reoiling should follow the manufacturer's care instructions, and dirt should not be allowed to fall into the housing during the swap.
