Since the engine air filter is a part that needs to be replaced pretty frequently, you've probably wondered at some point if aftermarket air filters are worth the few bucks in savings. This comparison guide will satisfy your curiosity. We'll talk about the 3 most important factors to look for while shopping for engine air filters and see how aftermarket air filters stack up against OEM ones.
Image Credit: Engineering Explained
Fitment is arguably the most important part of an air filter. It has to be the right length, width, and thickness in order to leave no gaps. If there are gaps between the filter and filter housing, then dirty air can get through to the engine and damage it. More specifically, some engine components will wear out faster, which decreases performance and increases oil consumption.
Since OEM engine air filters are designed by Subaru, they fit perfectly each and every time. A 2010 Forester owner named C.B. Long is pleased with his OEM air filter. He wrote, "[My air filter is a] genuine Subaru part, so fit was good, as expected." Another Subaru owner observed that his OEM air filter "looked identical to the OEM [air filter] in the vehicle (other than being cleaner)", and noted that it "fit perfectly".
Since OEM engine air filters fit so easily, they take no more than couple of minutes to install. So if you get an OEM engine air filter made specifically for your Subaru model, you'll have the peace of mind that you won't experience any fitment issues.
You can't really say the same about aftermarket engine air filters. They're notorious for not fitting so well. Amazon is loaded with complaints about poor-fitting aftermarket engine air filters:
- An Amazon user named Sam observed that the frame of his aftermarket engine air filter was just a bit thicker than the OEM one. "When you try to close the filter housing, there is a gap around it," he wrote in his Amazon review. "This means dirt and water will enter into the housing. To make it work, I wrapped the housing in electrical tape to keep out the water and dirt. It was past the return interval so I'm stuck with the air filter."
- A 2018 Forester owner named John Wilson noticed that the plastic frame of his aftermarket engine air filter was about 1/8" thicker than the OEM air filter. It prevented the housing box from closing completely. "I tried for 30 minutes to [get the aftermarket filter to] fit, and it would just not work. The original Subaru filter went back in easily."
- An Outback owner noted in his Amazon review that the rubber seal on his aftermarket engine air filter was too thick and too stiff. As a result, he had a hard time closing the housing. "You will literally hurt yourself and swear silly trying to install it," he wrote. "Very poor design."
2. Material Quality
Material quality is another important part of an engine air filter. The filter material is solely responsible for trapping the dirt and debris before the air makes it into the engine. Other materials, such as seal adhesive, matter too. The adhesive attaches the filter to the rubber seal. If the adhesive failed, dust would come though the gap.
Subaru spent a lot of time developing the perfect air filter material for their cars. Subaru's air filters are known for having thick and sturdy filter material. That's why OEM air filters last a considerable amount of time.
When it comes to the filter material quality in aftermarket air filters, it's hit or miss (mostly miss). A big reason why aftermarket air filters are so cheap is because aftermarket manufacturers aren't afraid to cut corners. A common way for them to save a few bucks is to outfit their air filters with cheap porous material that's easily tearable. With one of these air filters in your car, you'll see a lot more dirty air entering the engine.
"The adhesive for the seal on my aftermarket engine air filter is very weak," a WRX owner named Ryan Taylor wrote in his Amazon review. "Part of the seal became unattached in several places while I tried to slide the filter into place. After fiddling with it for way too long trying to get the air filter box to close up properly, I couldn't get it in. I was uncomfortable with the seal not being attached in places, so I gave up and put the old filter back in for the time being, which was super easy as it should be." He ended up ordering an OEM filter.
3. Pleat Count
When shopping for an engine air filter, you want to look for deep, tightly packed pleats. The deeper the pleats are and the more tightly packed they are, the more filter material there is. You want as much filter material as possible because there's more room to trap the dirt and debris. That means the filter will last longer. Subaru is pretty good at ensuring that their engine air filters are packed with deep pleats. Aftermarket manufacturers aren't usually concerned with adding as much filter material as possible to their air filters.
When you take a look at the three most important factors to consider while looking for an air filter, it's easy to see that OEM is the much better option. Aftermarket air filters are rarely worth the few bucks in savings.
The good news is that OEM air filters don't always have to be pricey. We're authorized sellers of genuine OEM Subaru parts, including air filters. We're able to offer wholesale pricing on all of our parts. Check out our catalog of air filters to see how much you can save on a genuine OEM engine air filter for your Subaru!