When Should You Change Your Car’s Air Filter? (How-To Guide)

Air Filters 101 - Featured Image

Has a car care professional ever changed your engine air filter? Most likely, you were probably getting your oil changed when a mechanic showed you how dirty your current air filter is, and suggested you get a replacement.

While there’s nothing wrong with paying someone to replace your car’s air filter, it’s also money you don’t need to spend. Changing a car’s air filter is incredibly easy, even if you’re a total car care beginner. Here’s everything you need to know:

Air Filters 101

You and your car have something in common: You both need oxygen in order to move. Internal combustion engines require a steady intake of clean air. The air mixes with gasoline (or diesel) and then a spark plug creates a spark which results in a tiny explosion. These tiny explosions are what powers the engine.

However, the emphasis here is on clean air. But if you’ve been on a road, well, anywhere, you know the outside world is filled with dirt, pollen and much more. The air filter is designed to keep all of that debris out of your engine.

Filters are simple but durable and powerful. For modern cars, the filter will be a thick, paper-like material folded like an accordion inside a rectangular frame. They attach to the engine’s intake manifold (we’ll get into those details later).

The Importance of a Clean Air Filter

The air filter doesn’t seem like a super-serious piece of car equipment. And just how much damage can some dirt and pollen really cause, anyway? Well, even though the filter doesn’t seem particularly fancy, it plays a vital role in keeping your vehicle safe and operating at peak performance. Here are the three main benefits of regularly changing your air filter:

Fuel Efficiency is Improved

As you drive, your air filter blocks all the road debris. But that stuff doesn’t just disappear. It sticks to the side of the filter opposite your engine. A working air filter will naturally become dirtier over time.

After a few thousand miles, an air filter will typically start to clog. Air won’t be able to run through the filter as quickly or efficiently. The less air which reaches the engine, the more fuel which is required for combustion.

Changing your air filter regularly actually reduces your fuel consumption – often significantly so. Plus, buying new air filters is much cheaper than buying more gas at the pump.

Better for the Environment

Dirty and damaged air filters can cause your car’s emission control systems to malfunction. Your vehicle will expel more environmentally-harmful pollutants into the air. Changing your air filter actually helps make the whole planet a better place.

Helps Keep Engine in Great Working Condition

Tiny particles can cause big damage if they’re allowed to build up in your engine over time. An air filter acts as a shield, blocking debris from getting near sensitive components. Regularly changing your air filter can dramatically prolong engine life. Additionally, a clean air filter improves engine performance and acceleration.

When Should You Change Your Air Filter?

Generally, you should change your air filter every 12,000 miles or once a year, whichever occurs first. However, that’s just a general rule. Always follow the recommendations found in your vehicle’s owner’s manual.

Where you drive will also have a substantial impact on how often the filter needs to be changed. Do you drive mainly on well-paved roads in cities? Your air filter won’t need changing as frequently than if you’re a frequent off-roader. Plus, the overall air quality in your location will also impact changing needs.

Every 10,00 to 12,000 miles, take a look at your air filter. You don’t necessarily need to change it, but you do want to note its condition. After 20,000 miles or more, you’ll probably want to change the filter regardless of what it looks like. While some air filters can stay in good shape up to 50,000, replacement is cheap and easy. When in doubt, change it out.

How to Change an Air Filter (Even if You’re a Total Beginner)

First, congratulations on your willingness to try! Changing an air filter is easy and fast. But if you’ve never done it before, it can seem a bit intimidating. Don’t worry — we’ll walk you through each step.

1. Buy a New Air Filter

Air filters are sold online, at auto part stores and even most discount stores like Target and Wal-Mart. Simply buy one appropriate for your car’s make and model. There are four different, easy ways to find out this info:

  • Check your car’s owner’s manual
  • Check the car’s official website
  • Ask an employee (only at an auto parts store, not a retail store)
  • Use a nearby air filter book (looks like a phone book, sometimes found in the filter section)

Check out our complete guide to the best engine air filters for more detailed descriptions of specific products you’ll want to consider.

2. Locate the Air Filter Box

With your car shut off, open the hood. You’re looking for a black plastic box. It’ll usually be either on top or to the side of your engine. A giant hose will be sticking out of the side of the box.

3. Open the Air Filter Box

The box will have a few metal clasps. Simply unclasp them to open the box. You’ll see the air filter. Go ahead and pull the filter out. It should slide out easily by hand.

4. Inspect the Air Filter

How dirty is the current air filter? Don’t forget to check between the folds. If your air filter is barely dirty, you don’t necessarily need to replace it right now. However, as well said before: when in doubt, change it out.

5. Install the New Air Filter

“Installation” implies the process is a bit more complicated than it is. Simply place the new filter into the filter box. It should slide right into place without a problem. If you’re struggling to get the air filter to fit, double-check you have the right size. Once the filter is in the box, close the top and put the clasps back into place.

Replacing your air filter is a great D.I.Y. project which just about anyone can do. Simple and affordable, regularly changing your air filter will keep your engine protected from damage and running at maximum efficiency.

Brett Gordon

The engine behind editing at DigMyRide and the brains behind its build. During the day, Brett is a thirty-something dude from SoCal climbing the corporate ladder, but by night, he spends his time contributing to the online world of automotive tech & trends.