The K&N 33-2366 is a panel-style replacement element built from multiple layers of premium cotton gauze that drops into the factory airbox of the 4.0L V6 Ford Explorer, Explorer Sport Trac, and Mercury Mountaineer. The manufacturer positions it as a high-flow filter that aims to boost airflow while keeping filtration strong enough to protect engine life, and lists overall filter efficiency at up to 99%. Its fit is the main reason to choose it over a generic paper filter, since it is sized for this airbox rather than adapted to it.
The purchase case against a disposable paper element is long-term cost. The manufacturer says the filter is meant to be cleaned and re-oiled rather than replaced, and lists a re-oiling amount of 1.16 oz (34 ml). The manufacturer's stated cleaning interval is every 75,000 miles under normal highway driving conditions, but published interval guidance varies, so confirm the schedule with the manufacturer for your driving conditions. Warranty terms are also described differently across manufacturer materials, so verify current coverage before buying.
According to the manufacturer, the 33-2366 is listed for the 4.0L V6 engine. The manufacturer's 4.6L V8 application for the 2006-2010 Explorer uses a different K&N element, 33-2353, so check your engine size before ordering.
The manufacturer states a cleaning interval of 75,000 miles under normal highway driving. Published guidance varies, and the manufacturer recommends confirming the interval for your own driving conditions.
The manufacturer describes this element as a drop-in replacement designed to fit the factory airbox, so no modifications are needed. Its vehicle page rates the job as easy, lists a screwdriver as the only tool typically needed, and estimates 5-10 minutes for the swap. Confirm your engine is the 4.0L V6 before buying, since the 4.6L V8 uses a different part. Plan to re-oil the filter using the manufacturer's stated 1.16 oz quantity when you service it.
