When to change Spark Plugs

By Julia Freeman

Spark plugs are one of those engine components that many people know very little about, apart from the fact that they are essential in the running of an engine. Some people know how a combustion engine works but it is really only mechanics that have an in-depth knowledge of how spark plugs can affect a vehicle’s performance.

Car engine

Replacing Spark Plugs

To understand when they need to be replaced, we need to take a more detailed look at the role of the humble spark plug.
 
Without a correctly functioning spark plug, your vehicle’s engine would not work. As the name suggests, a spark plug provides a spark, which causes the mixture of air and fuel to ignite. The spark is generated by passing electricity between two terminals which are close enough for the electricity to jump across them, but not so close that they touch. Igniting the mixture results in an explosion that pushes the pistons in your engine, generating the power to propel the vehicle.
 
Although spark plugs are such as essential component, they should only need to be replaced between every 30,000 to 90,000 miles. Even when replacements are needed, spark plugs are inexpensive, and installation of new spark plugs is not a big task for qualified fitters.

What are the symptoms of a failing spark plug?

If your spark plugs are nearing the end of their useful lives, there are several issues that you may experience when driving:

  • Your car may feel rough when it is idling, with a potentially bouncy or shaky feel when the engine is running, but the car is stationary.

  • Your engine may feel like it is misfiring or jerky when accelerating.

  • You might find the car is lacking power even though you are pressing hard on the accelerator.

  • You might notice an odd smell from the engine.

  • You might find it difficult to start your car.

In each of these cases it could be that your spark plugs are not producing a strong enough spark to ignite the fuel mixture effectively.
 
Finally, if you notice that your fuel economy has fallen dramatically without any obvious cause, it may be time to fit a new set of spark plugs.

What happens after the new spark plugs have been fitted?

Once you have had your new set of spark plugs installed, this should result in optimal combustion in the engine. Your car should start at the first turn of the key and you should notice an improvement in fuel economy, a smoother ride and predictable power when accelerating.
 
A new set of spark plugs can improve your fuel efficiency by up to 30%, meaning that they are great for the environment as well as your wallet.
 
If you need to change your spark plugs, get in touch with your local Protyre garage. We can also supply and fit tyres from manufacturers such as Bridgestone, Pirelli and Sumitomo as well as carrying out a free tyre safety check to ensure your tyres are in a safe working condition.

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About the author

Article Author Photo
By Julia Freeman
Julia is Head of Retail Marketing for Protyre and loves engaging with customers and the business as a whole to make sure Protyre is more than just a local garage.
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