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The Ultimate Guide: A-Z of Car Parts – Part One

Whether you consider yourself an amateur mechanic or you have no clue what is going on underneath the bonnet, it definitely pays to have a basic knowledge of how your car works and what different parts do. In this series, we take you through the main parts of your vehicle, their definition, common problems and how (or if) you can fix them. Follow Trust A Garage on Facebook or Twitter for the full A-Z (or, to be more accurate, A-W) of car parts.

Air Filter (Engine)

Definition: The engine’s air filter stops dirt and debris from getting into the engine and impeding its function.

Common problems: Like any filter, over time the engine’s air filter can become clogged up with dirt and dust, which will affect its ability to draw clean air into the engine. Signs of a blocked filter include unusual engine sounds, black emissions, or reduced mpg.

Quick fix: The average engine filter will last around 3 years or 30,000 miles, less if you spend a lot of time sitting in heavy traffic. It is relatively easy to replace your engine filter; check your handbook for specific instructions and make sure you get the right part before locating and replacing the filter. It is also possible to buy long life air filters made of cotton or foam which can be cleaned and reused rather than being replaced.


Definition: It is the battery’s job to get your engine started, but the alternator is responsible for getting power to the other electronic elements, such as lights and windscreen wipers, as well as recharging the battery once the engine is running.

Common problems: As alternators play such a key role, there are a few common problems that can result in the alternator failing and the engine stalling. Before this happens, your battery warning light will come on; you probably won’t get much warning, so as soon as the light comes on, get to your local garage to get it checked out and avoid breaking down. While the alternator failing is a serious problem, it is usually relatively easy to fix, and is usually down to loosened drive belts, worn bearings or connector faults.

Quick fix: You really need a mechanic's knowledge to replace an alternator. While some older vehicles are easier to fix than others, replacing an alternator requires specific tools. In this instance, it is best to leave the job to the professionals. As soon as your battery light comes on, if you are confident that it isn’t your battery, get booked into your local garage.

Understanding your vehicle a little better can definitely improve the way you drive and, more importantly, the ability to rescue yourself in an emergency. Join our community of trusted garages and happy customers on Twitter or Facebook where we pick up with that all-important component, the battery.

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