What Happens if You Don’t Change the Car Air Filter? Expert Insights

When maintaining a car, one often overlooked component is the air filter. The air filter keeps the engine running smoothly by allowing only air through to be mixed with fuel for combustion. It might surprise you, because it always surprises me that people manage change the oil filter, which is much more challenging to change than the air filter. But, somehow, drivers often forget to change or even clean it at the very least. 

If a car’s air filter is never replaced, it can lead to various issues. Over time, the filter gets clogged with dirt, dust, bugs, and any other debris it can filter, all restricting airflow to the engine. This can cause a decrease in power, acceleration, and reduced fuel efficiency. In a worse case, a dirty air filter can cause the engine to run hotter if left for prolonged periods, leading to overheating and potential engine damage.

What Is a Car Air Filter?

A car air filter usually contains foam, pleated paper, or cotton fibers. Its primary purpose is to stop the engine from combusting harmful particles such as dust, dirt, pollen, bugs, and other debris by collecting them. 

An engine requires three things to work, a spark delivered by the spark plugs, the fuel, and oxygen; remove one of those, and you don’t have a running engine, don’t supply enough of, or an insufficient amount of one and the engine won’t function as it should. The filters job is more critical than you might think.  

What Happens if You Don’t Change the Car Air Filter?

If you neglect to change the air filter, you could face several issues, such as:

  • Reduced Fuel Efficiency

Reduced fuel efficiency happens because the air filter blocks up with dirt and debris, which means that the engine has to work harder to draw in air. The engine will work harder and have an imbalance in the air/fuel ratio combusted. The car will start to burn more fuel-air, meaning you may notice you visit the gas station too frequently.

  • Decreased Engine Performance

A clogged air filter can also cause decreased engine performance. When the engine can’t get enough air, the engine will essentially be getting strangled. This can cause sluggish acceleration, reduced power, and poor overall performance. 

  • Increased Emissions

If the air filter is especially blocked, the engine may not be able to burn fuel efficiently because it is not getting enough air. An increase in car emissions will follow, which is harmful to the environment. Your car could fail an emissions test because of an air filter issue, although this is in theory, and I am yet to see this myself. 

  • Damage to Engine Components

If the air filter is filthy or old, it will be weak, which may result in the filter tearing, allowing debris to be forced through it and enter the engine. Damage to engine components, such as spark plugs, pistons, valves, cylinders and a clogged throttle body, can occur. The amount of damage a tiny rock will do is unreal; it can destroy an engine. 

  • Overheating

If the car overheats because it is compensating for the lack of air getting through the filter by using more fuel, the head gasket is at risk of failing. Alongside other issues that can be caused by neglecting to change the filter. 

clean or change the air filter

How Often Should You Change the Car Air Filter?

Changing the car air filter is an essential part of car maintenance. Changing the air filter once a year, or every 12 – 15000 miles, is recommended, whichever comes first. However, if you regularly drive in dusty or polluted areas, you may need to change it more frequently.

It is important to note that neglecting to change the air filter can also lead to costly repairs. A clogged air filter can cause the engine to overheat (very rare), resulting in a blown head gasket or other damage. 

If it is not possible to change the filter within the recommended time frame taking the filter out and blasting it with some compressed air will help to remove some of the debris caught in it. 

Hoovering the filter can also work. Just be careful not to tear a hole; if the filter gets damaged, throw it in the trash. It’s not worth the risk of sucking a bit of debris into the engine and destroying it.


Neglecting to change the car air filter can severely affect the vehicle’s performance and longevity. Replacing an air filter is a straightforward task that requires very little car knowledge. An air filter is inexpensive, so there should be no reason not to replace it yearly. 

My name is Tom although my friends call me Tommy. Messing around with cars and bikes has always been a hobby of mine even from a young age. So I made it my day job 17 years ago. I am a fully qualified mechanic as you would expect. I've worked in all different areas of the motor trade, valeting, panel beating, engine repairs, I'm sure you get the idea. I enjoy sharing my wealth of knowledge and experience with others, which is the reason I spend a lot of time here writing for this website.

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