Much like the air filters used in homes and offices for furnace or air conditioning systems, car air filters help stop unwanted particles or contaminants from entering the engine or HVAC system of your vehicle. Over time, the gunk and debris that collect in these paper, cotton, or synthetic fiber materials causes them to cease performing these essential tasks, which is why they need to be replaced periodically based on your driving habits and manufacturer recommendations.
There are two primary types of air filters in your car. Each one is vitally important to your car’s overall health and performance.
Engine Air Filters
The air filters that protect your engine are located under the hood in a rectangular box near the front of the engine compartment. They are designed to prevent grime from the outside from contaminating the complex operating system that keeps your vehicle running every day.
Fundamentally, the engine filter helps your engine breathe more easily. Without a consistent flow of clean air, particularly oxygen, the fuel that powers your engine won’t burn properly. If the above-mentioned debris was to get into your car’s engine, it would starve it of air and cause a noticeable drop in performance. This could take the form of decreased power and acceleration when you hit the gas or an overall sluggish feeling when driving down the road.
Studies show that dirty filters do not have a significant impact on gas mileage. In theory, however, a severely clogged engine filter could cause your car to stop working altogether. More realistically, it will result in corrosion of the internal parts inside the engine—outside particles can wear away at your engine’s metal bearings, piston rings, and cylinders—and lead to expensive (and probably preventable) repairs down the road.
Keep this in mind: Replacing an engine can cost thousands of dollars, while replacing your engine filters regularly costs $40 to $80 at a repair shop. If you’re a DIY type and want to tackle this relatively easy task yourself, the cost is even cheaper.
Cabin Air Filters
These filters focus on keeping dirt and small particles from entering your car through the vents, as well as preventing things like leaves, bugs, and other outside materials from clogging up the HVAC system itself.
In most vehicles, there is no warning light that says when a cabin filter needs to be replaced. That’s why some vehicle owners simply have their filters changed every time they get their oil changed as part of their regular maintenance routine.
However, there are some telltale signs that your cabin air filter is clogged. This can take the form of reduced air circulation inside the car, a noticeable dip in performance of the heating and air-conditioning systems, or a high-pitched sound coming from the vents.
Similar to the engine filter, failing to change your cabin air filter can cause premature damage to your vehicle's HVAC system by causing it to work harder than it needs to because of the contaminants that have invaded its inner workings. But starving your HVAC system of clean fresh air can also result in a musty odor inside your car due to poor air quality. This can be especially detrimental to allergy sufferers or those with respiratory issues.
While most people choose to simply replace their car’s cabin filter when it gets dirty, there are reusable filters on the market that can be cleaned and reused.
Similar to engine air filters, the cost to replace a dirty cabin filter typically ranges from $40 to $80, depending on the make and model of your vehicle, and whether you perform the job yourself or hire a mechanic.
When to Change Your Air Filters
Because of the importance of air filters in relation to the performance of vital parts of your vehicle, these are not the type of maintenance items you should put off if you can help it.
Modern engine technology provides vehicle owners with a certain degree of leniency, but most car and parts manufacturers recommend changing both engine and cabin air filters every 12 months or 12,000 miles. However, those who regularly travel dirt roads or areas high in pollution, or those who suffer from allergies, should consider changing their filters more frequently. Some experts prefer changing air filters as often as every 3,000 miles. To be sure, check your owner’s manual.
As a general guide, make sure either you or a trusted mechanic is at least inspecting your vehicle’s air filters every 6,000 miles.
Keep Your Vehicle Happy and Healthy—Inside and Out
Air filter maintenance will help ensure the engine inside your car is performing as it should while the HVAC systems are properly cleaning the air you and your passengers breathe while traveling down the road.
Product Compliance and Suitability
The product statements contained in this guide are intended for general informational purposes only. Such product statements do not constitute a product recommendation or representation as to the appropriateness, accuracy, completeness, correctness or currentness of the information provided. Information provided in this guide does not replace the use by you of any manufacturer instructions, technical product manual, or other professional resource or adviser available to you. Always read, understand and follow all manufacturer instructions.