This is a reusable K&N panel air filter built around oiled cotton gauze, sized for the factory airbox of the 1986–1988 Porsche 944 S. The manufacturer describes it as a high-flow element that keeps filtration high while improving airflow, and it uses multiple layers of treated cotton gauze to trap contaminants. Although the catalog title says "Volvo," the manufacturer's application listing names only the 944 S 2.5-liter four-cylinder, so verify fitment before ordering. Choosing this over a disposable paper element means you wash and re-oil one filter rather than buying replacements, and the manufacturer's highway cleaning interval is long. Search terms this part matches include K&N 33-2640 944 S panel filter, washable 944 S intake filter, and 944 S 2.5L drop-in air filter.
Installation is a drop-in swap. The filter arrives pre-oiled and is designed to sit in the stock airbox, so you remove the paper element and seat the K&N in its place. K&N's instruction sheets for other panel filters call for cleaning the sealing surfaces, seating the filter fully, and closing the lid securely, so follow the sheet packed with your filter for this part's exact orientation. Because the airbox seal affects both filtration and engine protection, a clean and properly seated install matters more than the filter brand alone.
The manufacturer's application listing for 33-2640 names only the 1986–1988 Porsche 944 S with the 2.5L L4. The Volvo wording in the product title is not reflected in that listing, so confirm with the manufacturer before ordering for any other vehicle.
The manufacturer states a cleaning interval of about 75,000 miles under normal highway driving. Harder or dustier conditions shorten that interval, so inspect the filter regularly.
The manufacturer's product page lists a No-Hassle Lifetime Limited warranty, while its Porsche 944 S category page references a Million Mile Limited Warranty. Coverage terms vary, so confirm current details with the manufacturer.
The manufacturer describes this as a drop-in replacement for the factory air box, so no modifications are expected. Remove the stock element, clean any dust or debris from the airbox sealing surfaces, set the K&N in place, and close the lid so it seals evenly. Confirm the orientation against the instruction sheet included with the filter. Tools and specific torque or lid-clip details for this 944 S application were not confirmed in the manufacturer material I could verify, so check the included sheet before starting.
