What is an Engine Air Filter : Complete Beginner Guide

An internal combustion engine needs air and fuel in proper proportions known as stoichiometric ratios, to carry out the combustion process which generates the required amount of energy to drive the vehicle from one place to another. 

The overall efficiency of an engine is strongly dependent on how the combustion is taking place and the quality and quantity of air defines the quality of combustion. Engine must be supplied with clean and sufficient air for proper combustion. 

This is where the engine air filter plays a vital role in providing clean air for combustion. To know your car best you should know what is an engine air filter? What does engine air filter do? its types, location and how often to change it.

Engine air filter

What is an Engine Air Filter?

An engine air filter is an important part of an engine that restricts the entry of dust and debris into the engine cylinder where the combustion takes place. It comes in various shapes and sizes and can be made of different materials such as paper, foam or cotton. 

Engine air filters made of paper are the most common amongst all other types as they are efficient and have lower cost compared to other available filter types. The shape and size of an engine air filter changes with the make and model of a vehicle but it is usually made rectangular or cylindrical. 

Furthermore, an engine air filter is made in a pleated or folded shape to increase its area to capture the dust and debris and manage the required flow of the air.

Engine Air Filter

What Does an Engine Air Filter Do?

A clean and quality air inside an engine cylinder is extremely important to maintain the quality of combustion, increase the fuel efficiency, enhance the engine power, increase the engine’s life, and reduce the discharge of unburnt hydrocarbons at the exhaust of an engine. 

An engine air filter is installed at the suction side of an engine and it stops dust and other unwanted particles from entering the combustion area of the engine i.e. cylinders. 

These unwanted filtered particles are collected at the pleated or folded surface of the filter and are usually cleaned after regular intervals to let the air flow properly through the engine air filter. 

If a filter is not clean or clogged with dust and debris, it will restrict the airflow through itself which will decrease the efficiency of the engine.

Types of Engine Air Filter? 

There are several types of engine air filter available in the market. The use of a specific air filter is dependent on the type of vehicle, its model and driving conditions. 

Shape of an Engine Air Filter

An engine air filter can be classified as rectangular and cylindrical based on its shape. A cylindrical engine air filter has a shape like a cylinder whose both ends are open. Such filters offer large surface area and have compact size which enables them to fit into tight spaces in an engine. 

Whereas a rectangular engine air filter with one or both ends open is more common than cylindrical shaped air filters. It must also be noted that some engine air filters may have unique shapes or features to fit specific engine configurations or to optimize airflow and filtration efficiency.

Material of an Engine Air Filter

An engine air filter can be made from different materials such as paper, foam, cotton or any appropriate synthetic material. Paper air filters usually made of PET (Polyethylene terephthalate) fiber are the most common amongst all the air filters. 

Foam air filters are made of polyurethane and can be reused up to several times. Cotton gauze air filters made up of multiple layers of cotton gauze are considered to be the most efficient engine air filters and are usually used in high-performance vehicles. 

Oil-bath engine air filters are also available in the market and are most suitable for dust-laden environments. Furthermore, most of the engine air filters are made pleated or folded to increase their surface area but non-pleated engine air filters have also been used. 

Similarly, most of the engine air filters can be reused after cleaning whereas few of them always need to be replaced after a certain amount of time or mileage of the vehicle.

Location of an Engine Air Filter?

Location of an engine air filter in a vehicle does not change greatly with the change in the model or the manufacturer of the vehicle. Front engine vehicles are the most common amongst all modern vehicles therefore an engine air filter should be looked under the hood of a vehicle. 

An engine air filter is usually very easy to locate. Lift the bonnet of your vehicle, and search for engine air filter housing. Air filter housing is usually a black box on the top or toward the side (right side preferably) of the engine. 

The air filter housing box usually has a tube connected to it which makes it easy to locate the engine air filter housing in a vehicle.

On the other hand, mid-engine and rear-engine vehicles are less common but in that case engine air filters will not be found under the hood but must be looked at within the engine area.

How often to change engine air filter?

Like any other part of an engine, an engine air filter has a working life after which its performance curve starts to go down. So how often to change engine air filter? An overused air filter will not be able to allow the incoming air to enter the engine easily due to its clogged surface which will affect the performance of the engine. 

Different types of engine air filters made of different materials are available and their working life span is not similar to each other. The life of an engine air filter also depends on various factors such as driving conditions, environment, and the quality of the filter. 

In general, paper air filters are designed to last between 10,000 to 15,000 miles (16,000 to 24,000 kilometers) under normal driving conditions. 

To replace filter with new one we recommend to buy the best one after complete search of engine air filter. An engine air filter made of cotton is washable and reusable and typically has a longer lifespan compared to a paper filter. 

Depending on the quality of the filter and driving conditions, a cotton air filter can last up to 50,000 miles (80,000 kilometers) or more before needing to be cleaned and re-oiled, which can extend the filter's life even further. 

However, it's essential to follow the manufacturer's recommendations for cleaning and re-oiling to ensure that the filter is functioning correctly and not causing any damage to the engine.

Similarly, engine air filters made of foam are also durable and long-lasting, but their lifespan can vary depending on the quality of the filter and driving conditions. 

Foam filters are also designed to be washable and reusable, and with proper maintenance and cleaning, they can last for several years or more.

Concluding the Engine Air Filter

Now you know what deliver a clean air to your engine for combustion. You should change your cabin air filter as and when required with a compatible and recommended engine air filter.