Imagine you’re out for a jog and you suddenly run through a cloud of dust. One deep breath and you’ll be coughing and searching for a breath of clean air. Inability to breath freely will certainly slow you down, and the same goes for your car. Your car wouldn’t run well if it was constantly inhaling dust and dirt. That’s why your car’s engine has an air filter in the air intake system to make sure that your engine is always breathing clean air.
Function of an Engine Air Filter
Air is vital to your car engine’s function. Without it, the combustion process could not occur and your engine simply wouldn’t run at all. The engine air filter’s function is to prevent airborne particulates such as dust, pollen, and bugs from entering your engine which both prevents damage to the internal components of your engine and makes the combustion process much cleaner and more efficient. Most air filters are made with pleated paper, foam, cotton fibers, or spun fiberglass filter elements to allow for maximum filter surface area to increase the amount of time it takes before the filter becomes clogged.
Common Symptoms of a Bad Air Filter
Lower Fuel Mileage – One of the first things that you’ll notice from a dirty air filter is a reduction in fuel mileage. A bad filter won’t allow as much clean air to enter the engine as a clean one will, which reduces engine efficiency. You’ll notice fewer miles per gallon and fewer miles per tank of fuel.
Lower Engine Performance – Because efficiency drops as less air enters your engine due to a bad air filter, the engine just can’t perform as well. A clogged filter will continually reduce the amount of air going into the engine which means less efficient combustion. This will manifest itself as a motor that feels sluggish with slower throttle response and less power.
Filter Looks Dirty – One of the easiest ways to monitor the health of your engine air filter is just to look at it. Most new filters will be a bright color (white, pick, yellow, orange etc.) with nary a speck of dirt on them. As they filter more and more contaminants, they will start to turn brown or gray due to the captured particles that have become stuck in the filter. If you notice that the filter is becoming clogged, it’s time to grab a new one and keep your engine performing well.
Replacing an Engine Air Filter
When you’ve determined that your air filter needs to be replaced, the process should be relatively easy to complete with a minimal amount of hand tools and in a short period of time.
Note: The example steps below are intended for general informational purposes solely to help give you an idea of project difficulty and tools required. As all cars are engineered differently, repair procedures and safety hazards vary from vehicle to vehicle. To ensure that you have a vehicle specific repair procedure and an exhaustive list of potential safety hazards, we advise you reference a factory service manual for your vehicle. Similarly, referencing a repair manual such as Chilton or Haynes might serve as a less expensive alternative.
Step 1 – Locate the airbox within the engine bay of your vehicle. The filter is usually contained within a plastic box shaped housing (hence the term airbox) although there are exceptions on some vehicles. The airbox usually has an intake tube attached to the box that draws in fresh air from the front of the vehicle, and a similar tube that exits the box and routes air to the intake manifold.
Step 2 – You’ll need to remove the airbox lid to access the filter. The lid could be attached with screws (for which you would need a screwdriver to remove) or with clamps that you need to unsnap to get inside the airbox. Some vehicles may also require removal of the intake tubing to get proper access to the filter. The intake tubing could be held on with a hose clamp and also may require a screwdriver to take off. If using tools to remove, be careful not to damage the tube, especially if it is made from rubber or silicone.
Step 3 – Once you have the lid off and can access the filter, you need to remove the filter from the airbox. It may lift out or slide out depending on the vehicle.
Step 4 – If you have a common paper or foam filter that doesn’t require additional preparation other than just removing it from the packaging, you can replace the old filter with a new filter. Also check the airbox interior for additional contaminants like dirt or bugs. If there are any in the airbox, remove them before installing the new filter. You can do this easily with a small shop vac on a low power setting.
Note: Some specialized high mileage filters can require a quick cleaning and / or oiling and drying before installation. For these filter types, follow the directions from the manufacturer.
Step 5 – With the new filter in place in the airbox, you can then reverse the order of the above steps to put everything back together and complete the job. If you had to remove the intake tube, make sure to fully seat it in order to avoid any vacuum leaks otherwise you may end up spending time troubleshooting using a vacuum-pressure gauge.
Best Engine Air Filter Brands
When it comes to selecting the best replacement engine air filter for your vehicle, there are many brands out there to choose from and the decision can be a tough one to make. Some options available may seem attractive since they appear to be inexpensive, but cheap engine air filters tend to have a shorter service life. At the other end of the purchasing spectrum, there are brands that are expensive that aren’t always the highest of quality. How do you know which is the best value for you that provides the right mix between quality and price? To help narrow your search, we have provided a short list of our favorite air filter brands below as we have found them to be a good balance of quality and value over the years.
K&N has been producing air filters since the 1960’s and started as a small grass roots team racing motorcycles. Over the last 50 years they have expanded into other types of filters, such as cabin filters, oil filters, and more recently cold air intakes to complement their air filter line-up. They have two different product lines of air filters with a replaceable / disposable line and then a 1-million mile serviceable (cleanable) line of filters. They offer many different filters for all sorts of vehicles, so they should have a low cost replacement option for your vehicle.
Fram is mostly known for their broad line of oil filters in the aftermarket. There’s a good chance that they are one of the brands you have had on your car at some point. Fram also has a large line of engine air filters, and they are typically on the lower end of the cost spectrum which makes them a nice budget friendly choice. They tend to provide decent quality for the money and are also pretty widely available so you don’t have to go too far out of your way to find them.
Mann is a global filter manufacturer that started in Germany in the late 1930s. Their filter lineup started with the original Volkswagen Beetle, but over the last 70 years has grown to include offerings for most vehicles across the globe. They manufacture high quality components for auto manufacturers, particularly German carmakers such as BMW and Mercedes. Their filters are in the middle of the cost range with great quality which makes them a high value option.