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One of the top maintenance items that folks seem to always get squeezed by dealer service departments for is replacing the engine air filter. On 99 percent of all cars, this crucial part of an efficiently running engine is a simple job that requires at most basic hand tools. Plus, even the most basic forms of DIY maintenance are fulfilling tasks (queue Jeremy Clarkson saying "I've mended something!"). So why not express some pride in self-reliance and tackle this service yourself? Here's how to do so.
Estimated Time Needed: Half an Hour
Good news, this is possibly one of, if not the, safest DIY job one can do on their own car. But still, there are sharp metallic and plastic edges all over an engine bay, so you might consider buying a pair of sturdy work gloves. We here at The Drive have had the joy and pleasure of slicing a finger or two while getting to fasteners on the top side of the engine more than once.
Everything You'll Need to Change Your Air Filter
Firstly, take a gander online and see what the job requires. You might be able to open the airbox with just a flathead screwdriver, but some have bolts or screws keeping them closed. Therefore, you might need a few things.
Again, not all of those are required, so be sure to research what sort of tools are needed to get to your car's air filter. If you own a Porsche Panamera, you'll have to do quite a bit more than just opening and closing the airbox.
Here's How To Change Your Air Filter
Let's hop to it!
Obtain the Replacement Air Filter
The first step is to get your hands on the proper replacement air filter, preferably of good OE quality. There are many parts retailers that sell them and some can show up at your door the very next day. Or, pop 'round to your local preferred parts retailer as there's a good chance they've got one in stock.
In our case, we grabbed an OE-quality Mann filter for this 2011 BMW 128i.
Do your research to see what tools are needed to open and securely close the air filter box. Then, have them ready by your side.
Open the Air Filter Box
Next up, undo the fasteners that keep the air filter box closed. In our case, because we're working on an annoyingly complex BMW, we had to undo the clamp behind the box, undo the bolts that hold it to the fender, and then unplug the MAF. Then, we were able to pull out the entire air box before removing its various Torx screws. We also removed the air intake piece to make life slightly easier.
However, most cars allow you to simply remove an easy-to-access cover to get to the air filter. Again, unless you own a Porsche Panamera. What's the deal with complex German automotive engineering?
Remove the Old Filter and Lightly Clean
Then simply pull out the old filter and marvel at the fact that it's probably a good idea that you're changing it. They often have all kinds of dirt and grime on the outside-facing side.
It's a good idea to clean the area of the filter box that sees outside air—less stuff to immediately stick to your squeaky clean new filter. Also, check and make sure there is no dirt or grime on the engine-facing side—it should be nice and clean since it's only seeing filtered air. However, all car parts wear out and fail, and filters are no exception. So if that side's dirty, clean it really well.
Cleaning could be as simple as wiping it with a shop towel or feel free to use a light cleaning solution that won't damage anything, like Windex or Simple Green. But don't use too much, and be sure to wipe it all up until the area's nice and dry before reinstalling everything.
Install New Filter and Button Up
Next, simply throw in the new filter and close it all up!
If you'd like to go a step further, this could be a good time to also remove the MAF, or mass air flow sensor, and spray it out with some MAF cleaner. This usually removes and installs just as easily as the filter, and is usually slightly upstream between the filter box and intake manifold, if not attached to the air filter box itself like in our case.
Ensure Everything Is Firmly in Place and Turn on the Car
Make sure the air box is sealed correctly and firmly. Once that's done, fire it up and take comfort in the fact that your engine will be breathing more efficiently.
For a solid visual representation of what the whole air filter replacement task looks like, check out this video by O'Reilly Auto Parts: