Changing air filters is one of those DIY things that is hugely satisfying. It’s easy, yet feels like you’re digging deeper into the nitty-gritty of your car. It’s almost as satisfying as changing the engine oil by yourself. Read on to learn everything you need to know about the things, plus how to maintain yours properly.
Air filters possess a very apt name. There is no ambiguity about what they do. They filter the air that is fed into the engine which ultimately helps power your car. Car trivia fact for you: for every kilogram of fuel your engine burns, it needs around fourteen kilograms of air. You can take that knowledge to the pub if you so wish.
An air filter keeps the air clean and protects your engine from swallowing and building up harmful debris. They contribute to keeping your engine clean, much akin to diesel injector cleaners. They do need to be replaced every so often, but you can usually clean them yourself to prolong their life.
The best Air filters at a glance:
Best cabin filter for small Fords: Mann CUK 2346 Activated Carbon Cabin Filter – buy from Amazon
The most durable sports filter: K&N Filters Performance Replacement Element – buy from Demon Tweeks
Best air filter cleaner: K&N Filter Cleaning Kit – buy from Euro Car Parts
In every annual service that you take your car to, an air filter change should be part of the work. And we don’t blame you if you service your car regularly and don’t fancy getting your own spanner set out. But if you do a lot of miles, it will be worth checking your air filter even before that service is due. Because how many miles of very dirty air filtration do you want to take?
How to find the correct air filter for your vehicle
Find the correct air filter for you
The easiest way to find out is to type in your car's registration number on Amazon Garage. It'll automatically register your car and display the correct air filters for you.
Pros
- Easy to search
- Lots of filters to choose from
Cons
- Delivery isn't free, unless you have Prime
The best air filters:
The best paper filter for VW Group vehicles
This one fits an array of VW products such as the modern Golf, Passat, Octavia, and even the Audi TT.
Pros
- Fits a lot of VW group cars
- Solid build
Cons
- Won't fit on a lot else
The best paper filter for BMW/Mini engines
Pros
- Ideal for smaller BMW group engines
- Easy to install
Cons
- Not suitable for much else
Best paper filter for modern BMW 3-Series'
Pros
- Suitable for quite a few BMW models
- Easy to install
Cons
- Won't fit anything else
The best cotton filter for VW group vehicles
Rrp: $64.99
Rrp: $64.99
This cotton alternative fits most modern 1.6 and 2.0 litre engine units from the VW Group, extending from Skoda, Seat to VW and Audi.
Pros
- Fits some VW group cars
- More durable than paper filters
Cons
- Won't be ideal for older engines of that manufacturer
The best air filter for most Ford vehicles
Rrp: $54.99
Rrp: $54.99
Pros
- Ideal for Ford owners
Cons
- Won't be suitable for much else
The best cabin air filter for small Ford vehicles
A clogged cabin air filter will be more noticeable to you than the one for your engine. If you notice the air from your air vents is no longer fresh, and perhaps your air conditioning is louder than what it was, it’s time for a new cabin filter.
Activated carbon filters stop particles, and gases, and eliminates odours. This particular cabin filter fits small modern Fords - the Fiesta, Puma, and EcoSport.
Pros
- Ideal for keeping cabin air clean in small Fords
- Easy to install
Cons
- Won't fit much else
The best cabin air filter for small Citroen/Peugeots
Pros
- Great for small PSA city cars
- Keeps cabin air fresh
Cons
- Won't be suitable for larger PSA group cars
The most versatile sports air filter
Despite racy appearances, they are effectively hyper-cleaners of air. They allow your engine to breathe more cleanly which at the best of times, might add one or two extra horsepower. If you're lucky.
Designed for a wide variety of applications, K&N's round tapered air filter is constructed using moulded pliable rubber flanges. This means they absorb vibrations and allow for a safe and secure fit.
It can also be stretched by 1.5cm and is washable - allowing for it to be reused. It can fit on a variety of vehicles from Minis to Mazda MX5s, allowing great versatility.
Pros
- Fits a wide array of cars
- Looks cool under the bonnet
Cons
- Don't expect a noticeable difference in performance
The most durable sports air filter
Designed to give your engine ultimate protection from dirty air as well as improving performance slightly, this filter has it covered. K&N claim that it will last 50,000 miles between cleaning, which if true, is quite incredible for one of the flimsiest parts of an engine.
Pros
- Incredibly durable item
- Tiny performance boost
Cons
- Only makes a minute difference in performance
Bets air filter cleaner
1. When the engine is cold, unclip and open the air box.
2. Remove the filter inside and clean the empty air box.
3. If checking the condition of the filter, make sure the filter is free from oil and dirt. If washing a cotton filter, follow the filter manufacturer’s instructions.
4. When putting in the new or cleaned filter, simply refit properly and pop the cover back on.
K&N's air filter cleaner comes in at stage 3. It's an aerosol that helps to dissolve the dirt and oil build up on your air filter. You must have the filter removed before applying the cleaner, before washing and rinsing it. Afterwards, you apply the oil filter coat across the air filter which adds a layer of protection against dirty elements.
Pros
- Effective in keeping cotton air filters clean
- Easy to use
Cons
- Not for use on paper filters
Replacement and maintenance of air filters
The mileage claimed by the air filter manufacturer and the recommended mileage for replacing or cleaning air filters in your car’s manual may vary. The general rule of thumb is to get your garage gloves on and replace a paper filter or clean a cotton one every year. At the very least, inspect it to check the condition. If you do low mileage, filters won’t necessarily have to be changed annually.
Cotton filters need to be re-oiled after cleaning. There are filter cleaning kits available, such as the one listed, that come with a cleaner to loosen dirt before washing, and oil to apply to the clean filter. Keeping your air filters clean and/or replacing them when needed is one of the ways you can keep your car’s emissions at a clean level.
How to replace your cabin filter
Cabin filters usually live behind where you could be storing a car maintenance guide book, the glovebox. Nevertheless, your car manual should tell you exactly where it is. YouTube is an excellent tool here, and you will be able to find a video on how to replace the cabin filter on your car model. It’s a two-minute job that usually involves unclipping the glovebox so that it fully unhinges like a snake’s jaw. Behind which you will find the cabin filter: pull the old one out, pop the new one in.
Aaron Hussain is a commercial content writer at Bauer Media writing for Parkers and CAR. He is obsessed with classic cars and anything with a fascinating story to tell.
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