Your Defender's engine is basically a big gas powered air pump. Air comes in through the intake and travels through the air cleaner/filter. Gas is added to the air and that mixture is compressed inside the cylinder. When the atomized mixture is at its densest, the spark plug is fired, which then ignites the mixture, and forces the pistons down into the cylinders. Dirty air filters can choke an engine, decreasing gas mileage and causing fuel deposits to form from bad mixture.

Newer reusable air filters are designed to increase horsepower and acceleration while providing excellent filtration. For example, K & N filters are washable and reusable, unlike the stock air filter that came with your Defender 110, and fit right into your existing Defender air box. Simply unlatch the three latches around the rim of your Defender air filter box, remove the cover, unscrew and remove the nut aft-plate holding your old filter in place, and dispose your old air filter. Apply a thin coat of air filter lubricant to your new reusable air filter and install it in place.