Most vehicles come with disposable paper air filters. When the time comes to change the air filter, the old one is simply thrown away and a new one is put in its place. K&N air filters are much more expensive than these disposable paper filters, but because the K&N air filters can be washed and reused instead of being thrown away, they will eventually save you money over the life of the vehicle. Some auto enthusiasts also believe that K&N air filters increase fuel efficiency and vehicle horsepower because they allow greater air flow than disposable filters.
Raise the hood of your vehicle, and prop it securely in place with the hood support.
Pull your new K&N air filter out of the box and look at the shape. It will be either square, rectangular, or in a few cases, it may be round.
Locate the large plastic box under the hood of your car that's the same shape as, and a little larger than, the K&N air filter. There should be a large-diameter hose leading away from the top half of the box. Usually, the boxes are closed with spring-loaded metal clips. This is the air filter housing.
Use your thumbs to flip back the spring-loaded metal clips that hold the top half of the air filter housing in place. Look on all sides of the casing to make sure you removed all the clips.
Lift the top part of the air filter housing off the bottom half. It may not come up very far, but there should be enough flexibility in the large-diameter hose leading away from it to let you lift the top part of the casing by at least 2 inches.
Remove the air filter from the air filter housing if there was one previously installed.
Note that there is a flat side and a protruding side to your K&N air filter. Place the air filter in the air filter housing with the protruding side oriented downward. It should sit solidly inside the housing.
Put the top of the air filter housing securely back in place. Make sure it sits firmly around all edges of the bottom part of the housing.
Flip the spring-loaded clips back into place. They should latch onto the top part of the air filter housing and hold it down. Check around all edges of the air filter housing to make sure you haven't left any spring clips dangling.
