Does it really matter if your air filter is clean or not? How clean is clean? How do you check your air filter? This article addresses these common questions and more.

Importance of Air Filters

An air filter is a very important part of a car. With old cars, like my 1931 Model A Ford, air filters were less important because the mechanical tolerances inside the engines were much less tight than they are today. A large particle of dirt could get into an old four-cylinder engine, and it may not do too much damage. In fact, I don’t even have an air filter on my Model A (they tended to catch on fire).

But today’s engines need good, clean air to run efficiently. So, checking the air filter is more important than you might think. An engine needs air, fuel, and spark, in precise combinations, to work properly. A clogged air filter reduces the amount of air flowing into the cylinder. This can cause your car to be sluggish or not run at all!

Checking the Air Filter

On most vehicles, checking the air filter is relatively easy. Most of the time, the air filter is located inside a protective housing on the top of the engine. Sometimes it is located elsewhere in the engine bay. Check the owner’s manual that came with the car for the location of the air filter. It’s usually very accessible. Usually, all it takes to remove the air filter is to flip some retainer clips or unscrew a wing nut (on older cars). Once you’ve taken off the cover, remove the actual filter, which is usually a web of fabric surrounded by a flexible rubber or silicone seal.

Carefully examine the filter. Often you can simply look at it and see if it “looks” dirty or not. If you cannot see light through it, change it! Some mechanics will use a very bright light, or even the sun, to see if they see any light coming through. If you are not sure how dirty it is, go ahead and change it. You cannot change an air filter too much. It’s the safest bet to change your air filter with a new one.

Replacing the Air Filter

Some mechanics will try to blow the dirt out an air filter to clean it. This is not a good idea. When I was training to be a mechanic, my teacher explained that when dirt gets trapped in an air filter, it can create a tiny hole in the filter. If you remove the dirt, the hole remains. This means you could have tiny holes in your air filter that could let more dirt through and into your engine.

Replace the air filter with the filter recommended by the manufacturer. You can also ask your friendly neighborhood automotive store employee. They have manuals to look up the proper air filter for your vehicle.

After getting the new air filter, simply place it in the protective case and snap it closed. This is the reverse order you used to take it out.

Final Thoughts

You can never change your air filter enough. Be sure to check it regularly. Your vehicle will thank you!


Written by Gary Pradel