How a Dirty Engine Air Filter Can Affect Your Vehicle

How a Dirty Engine Air Filter Can Affect Your Vehicle

26th Dec 2019

air filter on top of engine

Dirty Air Filters

When was the last time that you changed your vehicle's engine air filter? Not to be confused with the cabin air filter, this otherwise simple component is responsible for filtering the air that enters the engine's combustion chamber. When neglected, engine air filters will accumulate particulate matter to the point where it starves your vehicle's engine of air. While you can probably still start your vehicle, a dirty air filter can lead to several problems, including the following.

Poor Gas Mileage

You may experience poor gas mileage if your vehicle has a dirty engine air filter. Your vehicle will essentially run rich with a dirty air filter, meaning it will burn an excessive amount of fuel and not enough air. In some cases, a dirty engine air filter can lower a vehicle's gas mileage by as much as 10%.

Loss of Power

Automotive combustion engines need more than just fuel to operate; they need oxygen. With a dirty air filter, less oxygen will enter your engine's combustion chamber. And without a sufficient amount of oxygen, your engine won't be able to produce as much power.


In severe cases, a dirty engine air filter can cause or contribute to overheating. Like poor gas mileage, overheating is attributed to a rich-running engine. If your vehicle's engine air filter is clogged or otherwise dirty, less oxygen will enter the combustion chamber. As all the fuel burns in the combustion chamber, it can raise engine temperatures, potentially causing your vehicle's engine to overheat.

Whether it's caused by low coolant or a dirty air filter, you shouldn't drive your vehicle if the engine is overheating. Excessively high temperatures can cause catastrophic damage to your vehicle's engine. So, if you see the needle on your dashboard rising into the red zone, pull over and disable the ignition immediately.


A dirty engine filter can trip your vehicle's Check Engine Light (CEL). Again, this is because your vehicle will be running rich with a dirty air filter.  Your vehicle's onboard computer will detect the rich mixture of fuel and oxygen, and it may respond by illuminating the CEL on your vehicle's dashboard.

You probably won't experience all these symptoms with a dirty engine air filter. On the contrary, many instances of dirty engine air filters go unnoticed by drivers. Because of the role it plays in creating clean air for the engine, though, you should get into the habit of changing your vehicle's engine air filter on a regular basis as specified in your owner's manual.