How often should you change a car's spark plugs?

By Julia Freeman

An often-overlooked aspect of car maintenance is possibly one of the simplest jobs out there, as well as being vital to the starting and effective running of your vehicle.

car Engine Spark Plug

In addition to needing petrol or diesel to run, your car also needs electricity. Once you turn the key in the ignition, the spark plugs create an arc of electricity providing the spark to ignite the fuel, leading to the movement of the pistons in your engine, and allowing for motion of the vehicle. Without fully functioning spark plugs, your car will simply not run, or at best will run inefficiently, affecting both performance and fuel efficiency.

Wear and tear

In our experience, spark plugs will degrade over time, much like any other part of an engine. The most common part of a spark plug to wear out and eventually fail is the electrode. This part is the narrow, tapered end where the wire connects to the spark plug. The other end is where the action happens, with a rod and hook which produces the arc of electricity. Over time, the electrode becomes worn, so that to begin with less of an electric arc is produced, until eventually no arc is produced, and your engine will not be firing on all cylinders (which is where that phrase comes from), leading to reduced performance and eventually a breakdown.

How often should spark plugs be swapped?

As a general rule of thumb, the lifespan of a spark plug is around 30,000 miles, although there are a range of other factors which can affect this from the type of spark plugs installed to the way in which you drive.
High-performance spark plugs tend to wear out more quickly than standard plugs, due to the extra wear and tear the high output brings to the parts. On the other hand, long-life spark plugs can last for significantly longer, due to the fact that their electrodes are made of more resistant metals, such as iridium or copper.
Oil leaks in an engine can lead to contaminated spark plugs (amongst other performance issues), leading to more frequent changes being required. Similarly, if you are fairly heavy-footed, driving high in the rev range, you are likely to need to replace your spark plugs more frequently than someone with a lighter foot.

What to look out for

There are some issues with your engine to watch out for when driving which could indicate that it may well be time to replace your spark plugs, including your engine sounding as though it is skipping, running rough, or stalling for no good reason. Spark plugs can be replaced quickly by a mechanic, leaving your car in full working order in no time at all.

Book with Protyre

If your engine is sounding as though it needs some attention, why not contact your local Protyre centre and have our experienced mechanics can take a look. We also have an array of combined servicing and MOT packages available to suit every budget to keep your vehicle running safely and smoothly. You could even treat your car to a new set of Pirelli or Sumitomo tyres while it's with us if your old ones are worn.

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About the author

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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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