Open the hood. Find the air filter encased in a black plastic casing (typically around the size of a bread box) near the center-top of the engine (sometimes, however, it will be off to the side). Open the casing by sliding a flat-headed screwdriver between the casing and the large metal clips, then pry the clips away. Continue around the case's perimeter, loosening all the remaining clips. Occasionally you'll find an air filter housing that's held together with several long screws, in which case you'll have to unscrew them to get at the filter.

Pull out the filter — it's usually white, bright yellow, orange or red, to better to see the collected dirt. It can be flat and/or elongated, and is made of a paper element with rubber edges to seal it against the casing.

Next, check it for cleanliness. Hold it up to the light, bend it so the paper ridges of the filter flutter like the pages of a book, and look inside the crevices. Do you see a lot of accumulated dirt and grime? Now look at it straight on. Is the orange or yellow paper mostly dirty in the centre? If so, then you should replace it.

If you have not purchased a filter already, call a friend so he can bring you to your local NAPA Auto Parts store to purchase the right replacement part.

Slip the new air filter into the casing. Seal it up and you're done.