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How Does an Engine Air Filter Work?

How Does an Engine Air Filter Work?

How Does an Engine Air Filter Work?

Reading time: 7 min

Your engine’s air filter is one of the most important components of your machine’s air filtration system. It plays a crucial role in preventing harmful particles from entering the engine, ensuring that it runs smoothly and efficiently.

A dirty or clogged air filter can lead to decreased engine performance, increased fuel consumption and even damage to the engine.

In this article, we’ll explore the purpose of engine air filters in heavy equipment, why they’re needed and how they work to protect the engine from contaminants.

What is an Engine Air Filter?

An engine air filter is a type of filter that traps airborne particles such as dust, sand and silica, preventing them from reaching your machine’s engine. Engine air filters should not be confused with other kinds of air filters, such as cab air filters.

How Do Engine Air Filters Work?

Diesel engines require a steady flow of clean air in order to combust fuel and generate power. As you operate your machine, the engine takes in large quantities of air through its air intake system. This air is channeled into the engine where it is combusted along with fuel. If unfiltered air is allowed through the engine’s air intake system, however, dust or debris may make their way into the engine and contaminate the engine oil.

One of the most common and problematic airborne contaminants filtered out by engine air filters is silica. Silica is a fine particle found in dust and sand. It is also highly abrasive, making it a major threat to your engine if it gets into the engine oil.

Engine air filters remove silica and other particles from the air as it passes from the outside of your machine into the engine’s air intake system. This way, air filters keep the air flowing into the engine as clean as possible, preventing contamination of the engine oil.

Location of Engine Air Filter on Heavy Equipment

In most heavy equipment machines, the engine air filter is located in the engine bay, right next to the engine. Engine air filters are typically located in a designated air filter housing, which needs to be opened or disassembled to change out the filter.

The exact location of your machine’s engine air filter will depend on its exact make and model. You can find the location of the engine air filter by consulting your machine’s service manual.

Machines that Use Air Filters

All machines with combustion engines use engine air filters. Common machines that use air filters include:

  • Skid steers
  • Tractors
  • Backhoes
  • Loaders
  • Backhoe loaders
  • Trucks
  • Dozers
  • Excavators
  • Track loaders

Types of Engine Air Filters

Engine air filters come in a variety of types, shapes and sizes. The engine air filter you choose is based on your machine, your operating environment and your maintenance goals.

Inner Air Filters vs Outer Air Filters

In modern combustion engines, the engine air filter is actually composed of two individual filters – an inner filter and an outer filter. The outer filter is larger than the inner filter and the inner filter typically sits inside of the outer filter.

The purpose of the outer filter is to act as a first pass, filtering out the majority of large, airborne particles before they reach the inner filter. Outer filters are changed more frequently than inner filters. 

Sometimes called the safety filter, the purpose of the inner filter is to act as a filter of last resort should any dust or particles breach the first one. The inner filter acts like a safety mechanism, ensuring no stray particles reach the engine even if the first filter has failed.

Shapes and Sizes of Air Filters

Air filters come in various shapes and sizes, each designed to meet specific requirements of the engine they protect. Cylinder, flat and cone-shaped filters are the most commonly available filters on the market.

Cylinder-shaped air filters, also called round filters, are the most common filter shape used in heavy equipment. They have a round, cylindrical shape and are usually made of paper, foam, cotton or custom synthetic materials. Round air filters are easy to install and replace. Plus, they are typically less expensive than other types of filters.

While different filter shapes may offer unique advantages and disadvantages, the most important thing to consider is choosing an air filter that is compatible with your heavy equipment’s air intake system and the conditions it will operate in.

How Often Should Heavy Equipment Air Filters Be Changed?

To determine how often you should replace an engine air filter, refer to your machine’s service manual. On most filters, a visual indicator will pop up on the filter or the housing when it’s time to change out the filter. In modern machines, you may even be alerted by a light on the control panel when airflow to the engine has become restricted and the filter requires changing.

Referring to a filter gauge is the most accurate way to determine if an air filter should be replaced. Just glancing at a dirty filter won’t do you much good, since more build-up doesn’t necessarily mean more restricted airflow. Plus, excessively removing the air filter can lead to consequences, such as contamination from particles that get into the engine during removal.

Some fleet owners prefer to replace air filters at regular intervals according to a maintenance schedule. This strategy can help you avoid problems with airflow before they occur. EquipmentShare carries service kits for 50, 250, 500 and 1,000 Hour maintenance, many of which include replacement air filters for your equipment.

Symptoms of a Damaged Air Filter in Heavy Equipment

When to Replace Heavy Equipment Air Filters

Some symptoms of a damaged air filter in heavy equipment include:

  • Reduced Engine Performance: A clogged or damaged air filter can restrict the flow of air into the engine, leading to a decrease in power and acceleration.
  • Poor Fuel Efficiency: A dirty air filter can cause the engine to consume more fuel than necessary to compensate for the reduced airflow, leading to a reduction in fuel efficiency.
  • Engine Misfires: A clogged air filter can cause the engine to misfire or run roughly, causing shaking or rattling.
  • Unusual Engine Noises: A damaged or clogged air filter can cause unusual sounds from the engine, such as wheezing.
  • Warning Lights: Sometimes, the reduced airflow caused by a clogged or faulty air filter can trigger warning lights to illuminate on your machine’s control dashboard.

Another important symptom of a faulty or failing air filter is an uptick in silica present in your machine’s engine oil. Silica is one of the main particles filtered out by your engine’s air filter. If you’ve noticed a sudden increase in silica levels when testing your engine’s oil, it’s possible that a faulty air filter is to blame.

Importance of Preventative Maintenance for Air Filters

While air filters do not need to be changed according to a regular schedule, it is important they’re monitored to ensure they’re functioning properly.

As part of your preventative maintenance plan, make sure your operators are regularly inspecting their machine’s air flow gauges and any indicators associated with the air filters.

It’s also important to regularly test your machine’s engine oil, particularly for high silica levels. High silica levels are usually one of the first signs there is a problem with your machine’s engine air filtration system.

Can You Clean an Air Filter Instead of Replacing It?

Failing or dirty air filters should be replaced, not cleaned. Attempting to clean an air filter could damage the filter media, reducing its efficiency and potentially causing harm to your machine’s engine.

Engine air filters are delicate and specially-designed components that cannot be cleaned easily. In fact, cleaning a failing air filter instead of replacing it could cause more damage to the filter and engine than doing nothing at all.

Finding Air Filters in the EquipmentShare Online Shop

Proper engine air filtration is essential for the smooth and efficient operation of heavy equipment.

If you’re looking for replacement air filters for heavy equipment, look no further than EquipmentShare. Our online shop offers a wide range of air filters designed to fit a variety of heavy equipment makes and models.

We stock only high quality air filters from reputable manufacturers, ensuring that you get the best possible product. Don’t wait until it’s too late – visit EquipmentShare's online parts catalog for all your heavy equipment air filter needs.

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