Benefits of Changing Spark Plugs

April 26, 2023

Replacing an old spark plug for a vehicle.

Think about your vehicle’s spark plug as the lightning bolt that delivers the energy your car engine needs to start up. In more technical terms, your spark plug creates an electric spark across a small gap, which ignites an air-fuel mixture and makes the combustion that starts up your vehicle when you turn the key.

In other words, without a functional spark plug, your vehicle won’t start, much less take you anywhere. So, it’s safe to say the first benefit of changing your car’s spark plug is to ensure it can run.

However, that is not the only benefit of changing your car’s spark plug, and we’ll get into that soon. 

But, first, let us explore what continuous usage does to a car’s spark plug and see why it requires changing from time to time.

What Happens to a Spark Plug as It Ages?

Nothing lasts forever, and spark plugs are no different. Over time and with continued use, your spark plugs will experience general wear and tear, which will lead to a drop in their performance and, in turn, your car’s performance.

But what exactly happens to a spark plug as time passes?

Spark plugs typically have to experience and endure the most extreme conditions, including very high temperatures. Naturally, this affects the state of the spark plug, especially after extended periods. Of course, the more durable the spark plug material is, the longer it will last.

Nonetheless, every spark plug will eventually suffer from these two issues:

Deposit buildup

Remember, spark plugs are responsible for igniting a mixture of air and fuel in your engine’s cylinder. Over time, the spark plug’s interaction with this mixture will cause a buildup of carbon, fuel mixture, and excess oil, leading to an unreliable and jerky energy supply for your car. A common sign of this is engine misfiring.

A larger, harder-to-ignite spark plug gap

Before a spark plug can ignite, the electric spark has to jump across a small gap to provide the required combustion at the precise moment. However, as the spark plug ages, this gap may widen due to wear and the extreme temperatures in your engine. When this happens, your spark plug may be unable to produce combustion or may do so unreliably.

That said, let us examine some of the advantages of changing your vehicle’s spark plugs periodically.

Some of the Benefits of Changing Your Spark Plugs

The most obvious advantage is that your car will typically start without any problems (assuming there are no other issues). But, that is not all that matters. Here are some other upsides to changing your vehicle’s spark plugs when they wear out:

Improved Engine Efficiency and Performance

When the wear and tear on your vehicle’s spark plugs reach extreme levels, it generally reduces the performance of your engine. For instance, your car engine may start to misfire when one or more engine cylinders do not produce enough power. Other problems include rough idling and bucking.

Besides, worn-out spark plugs will also require higher ignition voltage to create the necessary combustion (if at all), which reduces the efficiency of your car engine. However, a new spark plug replacement will usually solve all these problems.

Better fuel efficiency

Experts have discovered that the engine misfires that old or worn-out spark plugs cause can reduce your car’s fuel economy by as much as 30%. In other words, no matter how good your vehicle’s fuel conservation design is, bad spark plugs will increase your fuel consumption.


Your engine will burn more fuel trying to help its spark plug generate a powerful spark to create combustion in the cylinders. Due to this, you’d generally experience more fuel refill expenses and may even have to deal with higher car maintenance costs.

Hitch-free engine ignition

This part may be pretty obvious. But, regularly changing your car’s spark plugs means you’d still not experience any issues with starting up your vehicle. Furthermore, you can also avoid related engine issues such as rough idling and poor acceleration.

Lower carbon emission

If you want to keep your car and do what you can to reduce your carbon footprints, replacing your old spark plugs with new ones is an excellent idea.

Old spark plugs put excessive pressure on your engine, leading to more harmful emissions from your exhaust. On the other hand, the Environmental Protection Agency reports that regular car maintenance and replacement of spark plugs can reduce the number of harmful emissions your car produces. 

Improved Horsepower

When you switch your old car spark plugs for new ones, you’d realize that your engine responds much faster to your controls, especially when you accelerate. In other words, you may notice a ‘boost’ in your car’s horsepower.

We’d level with you — new spark plugs will not increase your car’s horsepower. But, it can bring your engine back to optimum combustion and performance levels. This means your vehicle will accelerate better and live up to its horsepower rating.

Less Engine Deposit

The buildup of deposits on your sparkplug will attract corrosive elements, which settle on the spark plug itself and other parts of your engine. Over time, this can prevent you from getting optimum performance from your engine. However, you’d find that your engine is cleaner and runs more efficiently by replacing your spark plug regularly.

Better Cold Starts

A cold start occurs when you try to start your engine while its temperature is much lower than its typical operating temperature (usually due to cold weather). Your car batteries will most likely produce lower-than-normal electric currents in cases like this. In other words, your spark plug must create a powerful spark, or your engine will not start.

However, more often than not, older spark plugs may lack the capacity to get the job done. Thankfully, replacing them with new spark plugs will ensure your engine receives the combustion it needs during periods of cold starts.