Simple Filter Guide

filtersWhat are filters and what do they  actually do in your car, Suzanne Keane explains some of the most common ones

I love filtered water – and if you’ve ever seen the inside of a water filter you would understand why any part of your car that takes in air or liquid needs something to protect it from any bad things coming in too….. right? That’s where filters come in! Below you will find a list of the most common filters, and what they do.

Oil Filter –
Car Filter GuideOil is used to both clean and lubricate your engine. Over time it can collect debris, little bits of dirt and general nasty stuff. That’s why it’s so important to filter it, and to change the filter whenever your oil is being changed – there’s no point in having fresh new oil if it’s going to pick up dirt from your old dirty filter – and a dirty filter can clog and stop your engine from getting any oil!

Air Filter –Your engine will “breathe” in air, and since the air outside can be full of contaminents (and bugs) this needs to be filtered before it gets inside. Over time your filter gets clogged, which means your car won’t be getting enough air, which can in turn cause more problems! (lack of power, sensor issues etc.)

The good news is the air filter is probably the easiest one to change yourself. It usually lives in a plastic box either on top of, or to the side of your engine with what looks like a hoover nozzle attached (to suck in air). You may need to undo clips or screws to access it. More than likely your car will have a paper filter – you will see straight away if it’s clean or dirty. If you think it needs to be changed, shake it out to clear some of the loose dirt before re-fitting and get a replacement paper filter from a motor factors or your main dealer – you can dump the old one when you’re done. Don’t drive the car without a filter!

If you’re planning on keeping your car for a long time it may be worth investing in a cotton or foam filter – They cost more but are re-usable so rather than throwing them out you can wash them (with a special cleaning kit – not in the dishwasher!) when they get clogged so you never need to buy another air filter.

Fuel Filter –
A fuel filter makes sure that only the fuel actually gets from the tank into your engine. This is usually a clear plastic tub, with what looks like yellow crimped paper inside. If you can’t see into this it’s probably time to get a new one – although make sure to wipe down the outside to make sure the dirt is actually on the inside!
If you’re feeling confident you can change this one yourself using basic tools (screwdriver, clamps, something to plug the fuel pipes when the filter is off) – just keep in mind that fuel is extremely flammable and make sure you fit the new filter in the same direction as the old one!

If the fuel hoses are looking old make sure to replace them too. Run the engine for a few minutes after changing the filter to make sure nothing is leaking.

Pollen/Cabin Filter –
Now that you’ve made sure your car is only breathing the purest air you need to check on your own air! This filters the air that comes into the car through the a/c or vents. Your car may or may not have one, but if there’s a nasty unknown smell when you turn on the heating or you’ve got allergies it’s a good idea to investigate – and change the filter if your car is fitted with one.


Remember, if you’re confident with car maintenance and know your way around your own engine you will be able to change these yourself  – but if it’s the first time always ask an experienced friend to help out! 


Suzanne Keane



Author: Suzanne Keane

A confirmed petrol head with a penchant for Retro VW’s, Suzanne has been taking apart (and sometimes putting back together) her own cars for years! You can follow Suzanne on Twitter at @_suzannekeane

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