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Main Street Mechanic, Established 2005

All About Air Filters: Purposes, Signs Of A Dirty Filter, and Recommendations On When To Replace

Most everyone knows that replacing your vehicle’s air filters is a key maintenance item that shouldn’t be overlooked. However, few understand why the vehicle requires air filters, how often you should change them, and the difference between the engine air filter and the cabin filter. In this article, we’ll go over the purposes of the air filters, how often you should change them, signs your air filters are dirty, and benefits of regular air filter replacement.

A clogged or dirty air filter can cause issues for both you and your vehicle. A decline in health, a worsening of allergies or asthma, poor HVAC efficiency, loss of airflow, increased condensation build up on the windshield, and much more. Learn how to keep you - and your vehicle - in the best shape possible with regular air filter maintenance. 

The Cabin Air Filter

The cabin air filter is meant to prevent dust, dirt, and other environmental contaminants from the air you breathe within the vehicle. It is often located behind the glovebox and cleans the air as it moves through your vehicle’s HVAC system. It is a small pleated unit often composed of engineered material or paper-based multi-fiber cotton. All air passes through the filter before moving into the interior of your car. If you suffer from allergies, asthma, or other respiratory health conditions, maintaining the cabin air filter is especially important. 

The Engine Air Filter

The engine air filter is designed to prevent dust, dirt, and other environmental contaminants from getting into the engine. Contaminants in the engine or collected on the surface of the air filter can impede the airflow necessary for the car’s engine to function properly. It can rob your engine of power, including the ability to accelerate. A dirty engine can also cause overheating and engine choking. These are all reasons why regular engine air filter replacement is critical for the overall health and performance of your vehicle. 

Signs Your Cabin Air Filter Needs Replaced

If you notice a musty or unpleasant odor on your car as you’re driving, it may be caused by a dirty cabin air filter that’s ready to be replaced. Other signs include reduced or weak overflow, even when the heat or AC is set to full blast. Whistling sounds coming from the cabin air ducts often means the filter is ready to be replaced. If your heating and cooling system sounds excessively louder than usual, it is probably working harder to push air through a clogged air filter, in which case it’s definitely time to replace it.

Signs Your Engine Air Filter Needs Replaced

Engine air filters and cabin air filters are changed at different intervals so it’s important to watch for distinct signs pertaining to each. A decrease in gas mileage is one sign that your engine air filter is ready to be replaced. When the air filter is dirty, it’s harder to push air through the system and the engine has to work harder. If you’re noticing you have to fill up the gas tank more than usual, check your engine air filter. Another way is to simply do a visual inspection. If it’s looking dirty or full of debris, it’s likely time for a replacement. Ignition problems may be another sign that your engine air filter is ready to be replaced. A dirty/blocked engine air filter can gunk up the spark plugs and preventing sparking properly, leading to a sluggish or delayed ignition when you try to start the car.

How Often Should Cabin Air Filters Be Replaced?

Vehicle manufacturers all have different recommendations on how often your air filters should be replaced. Most recommend changing it every 15,000 - 30,000 miles. Check your owners manual to get the specific recommendation for your vehicle. You can also consult your local mechanics at Main Street Mechanic for more specific recommendations based on your location and driving habits. 

How Often Should Engine Air Filters Be Replaced?

Just like cabin air filters, engine air filter replacement interval recommendations will vary. For example, Hyundai typically recommends every 30,000 miles, but shortens that to 15,000 for severe driving conditions, such as heavy traffic in hot weather or frequent driving on unpaved roads or high smog places. Consult your local mechanic for specific recommendations.

Benefits of Regular Air Filter Replacement

Replacing air filters is an essential and cheap maintenance task that shouldn’t be ignored. A clean engine more efficiently than a dirty one! Regular air filter replacements will increase fuel efficiency, reduce emissions, prolong engine life, reduce noise in your vehicle’s heating and cooling system, prevent bad smells coming from your ducts, and improve the air quality you breathe while driving. 

Here at Main Street Mechanic, we are ready, available, and happy to inspect and help change your air filters whenever you need! We are currently running a Fuel Saver Special that includes tire rotation, BG Fuel Service, air filter replacement, and a gas cap test for only $169.99 (normally $260). Get more miles for your dollars! If you have any questions about your vehicle’s air filters and improving your vehicle’s fuel efficiency and performance, don’t hesitate to give us a call, message us on Facebook, or simply swing by. We are taking all necessary extra steps to keep our shop clean, sanitized, and safe for all our customers. If you have any concerns or questions or need to schedule an appointment, call 801-756-2661. 


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337 West Main Street
American Fork, UT 84003