What Does the Air Filter Do?

Changing the air filter

Your car's engine needs fuel and air to run, and it needs about 15x more air than fuel, by weight. In order to keep the internal parts of the engine in good shape for billions of revolutions, that air needs to be free of dirt, dust and contaminants. And in order to operate at peak power and efficiency, that air must flow freely into the engine.

Over time the air filter will get dirty and clogged as it traps particles in it and cleans the air going to the motor. Luckily, changing it is easy and rarely requires more than the most basic tools.

Every car is different, and detailed instructions are in the manual...

When to Change the Filter

Most manufacturers recommend that air filters are changed every 15,000 to 30,000 miles. However, the frequency depends on the conditions your car has encountered, and how hard it is driven.

The most important consideration for how often a filter needs to be changed is where you drive - if you find yourself off-road, driving dirt roads, in an area with smoke or pollution, or parking on an unpaved dirt lot, you are going to need to change the filter much more frequently. For most cars and drivers, changing the air filter with every second oil change is frequently enough, or at the very least, once a year.

Another thing to consider is that paper air filter elements can become restricted if they get water logged. If your car or truck has been driven through deep puddles you should check the filter for signs that it has gotten wet.

If the air filter becomes restrictive, both power and fuel efficiency will be lost, as the engine will have to work harder to get every once of air into it. The restriction will lessen the power and you will find yourself using more throttle to make up for it, burning more fuel in the process.

All cars are slightly different, so if it is time to change your filter, use our before you begin checklist, and find your car for specific instructions.

How To Change the Air Filter

This is a clip from a sample video. You will find the full step-by-step task for your model in the manual.

Here is a brief summary for most modern cars:

  1. Locate the air filter housing, typically at the end of a flexible plastic intake tube.
  2. Remove the screws, bolts, nuts, or spring clips holding the air filter housing together.
  3. You may need to disconnect the intake tube or other hoses from the housing.
  4. Separate the cover from the housing.
  5. Take note of how the old filter is installed, and remove it.
  6. Wipe dust and debris out of the housing with a rag.
  7. Install the new filter in the same orientation as the old one.
  8. Replace the housing cover and reconnect any hoses.

Before You Begin

Tools you will need

Only basic tools, if any, are required for this job:

  • screwdriver
  • nut driver
  • rag

Parts you will need

  • Air filter