How Much Does A Spark Plug Replacement Cost?

Spark plug replacement costs in the UK can range from £50 to £300.

These plugs help start your car by creating little sparks that ignite the fuel in the engine, making the car run. They’re a vital part of the vehicle, so don’t leave repairs up to guesswork!

Discover everything you need to know about spark plug replacement costs, including when to change them and what it will cost to buy and have them installed.

Key takeaways

How much does a spark plug replacement cost?

On average, a complete spark plug replacement in the UK costs between £50 and £300, depending on the type of vehicle and the number of spark plugs required.

The cost of a spark plug replacement comes down to the type and model of your vehicle. Luxury vehicles may require more expensive parts than standard models, while certain older cars may require specialised tools or engines for repair.

Here's an idea of average costs in the UK for spark plugs for different cars and makes.

Spark plug replacement costs by make and model

Spark plug replacement costs can vary significantly depending on your car’s make and model.

To give you a clear idea, here’s a guide to typical prices for popular vehicles in the UK. These may differ depending on your region and your car’s condition.

Car Make & Model	Spark Plug Replacement Cost
Fiat 500	£70
Ford Focus	£70
Toyota	£65–£70
Vauxhall	£200–£300
BMW 3 Series	£150
Volkswagen Golf	£80–£120
Audi A4	£120–£180
Mercedes C-Class	£150–£250

Spark plug replacement labour costs

Labour costs associated with replacing spark plugs can also vary depending on how long it takes a mechanic to complete the job. Some jobs might take longer due to difficult-to-reach locations in some engine compartments or tight spaces between components.

Vehicle Type	Estimated Labour Time	Typical Labour Cost
Small city cars	30–60 minutes	£30–£60
Family hatchbacks	1–1.5 hours	£50–£90
Luxury/sports cars	1.5–3 hours	£80–£150

Other factors affecting spark plug costs

Beyond car makes and labour costs, advancements in vehicle technology, such as direct injection systems, can make spark plugs harder to access, potentially increasing labour time and costs.

Additionally, the choice of spark plug brand and type can influence both parts and installation expenses.

If you’re worried about the costs of an expensive spark plug change, car repair finance can split these costs into interest-free repayments.

What do spark plugs do?

Spark plugs create sparks that ignite the air-fuel mixture in your engine, producing the explosions that power your car.

It goes without saying that they’re essential for starting your vehicle and keeping it running efficiently, so it’s important to keep them in good condition.

How many spark plugs are in a car?

Most cars have between four and eight spark plugs, typically one per cylinder, with the exact number depending on the vehicle’s size and engine type.

Electric cars, however, don’t need spark plugs at all, as their motors are powered entirely by batteries.

How often should spark plugs be changed?

Most modern cars need their spark plugs replaced every 20,000–40,000 miles, or roughly every three years.

Worn plugs can hurt performance and fuel economy, so check your owner’s manual or ask a mechanic if you’re unsure when to replace them.

Why do spark plugs wear out?

Over time, spark plugs wear out due to age, heat, and vibration caused by the engine's operation over a prolonged period.

To help your spark plugs last longer, adhere to your vehicle’s recommended service schedule, use the correct type of spark plugs for your car, and avoid harsh driving habits such as frequent rapid acceleration.

Regular engine maintenance, such as checking ignition coils and keeping the engine clean, can also prevent excessive wear.

How do you know if your spark plugs need changing?

If you notice any of the following symptoms in your car, then your spark plugs might need changing:

Your vehicle struggles to accelerate smoothly.
Overall engine performance has dropped.
Fuel efficiency decreases as the engine works harder.
Increased emissions from incomplete combustion release unburned fuel.
The engine idles roughly or misfires at low speeds or during acceleration.

What does a fault spark plug sound like?

A faulty spark plug may cause your engine to misfire, which produces a stuttering, popping, or knocking sound.

If you have a bad spark plug, you might also notice rough idling or unusual engine noises, especially when starting the car or driving at low speeds.

A good rule of thumb is to get your car checked whenever it starts making unusual sounds.

What happens when spark plugs fail?

When spark plugs go bad, they can cause a variety of issues with your vehicle's performance.

If a bad spark plug is not replaced, it can lead to further engine damage, which can mean very expensive repairs, such as:

Ignition coil failure

Catalytic converter damage
Misfiring cylinders
Poor fuel economy and increased fuel costs
Engine stalling or difficulty starting
Expensive engine rebuilds in severe cases

Are spark plugs worth changing?

Yes! Replacing your spark plugs comes with three main benefits:

Improved engine performance
Better fuel efficiency
Fewer emissions

It’s a simple, low-cost service that keeps your car running smoothly and helps prevent costly repairs down the line

Can I replace spark plugs one at a time?

No, when replacing spark plugs, it’s best to change the full set at once.

Replacing them individually or one at a time can affect your engine’s balance and performance, so it’s not worth the risk.

What happens if you don't replace spark plugs?

If you don’t replace worn spark plugs, your engine may struggle to start or misfire more often. It may also generally lose power. These misfires put extra strain on engine components, such as the pistons and valves, causing them to wear out more quickly.

You’ll also notice reduced fuel efficiency and higher emissions as the engine works harder to compensate. Over time, ignoring old spark plugs can lead to costly and potentially serious engine damage.

Can I replace the spark plugs myself?

Replacing your own spark plugs is generally not recommended unless you are an experienced mechanic.

However, if you choose to do it yourself, make sure you take all necessary safety precautions and follow the steps outlined in your vehicle's manual.

It can be tempting to replace your own spark plugs to save money and for convenience, but the task requires skill and knowledge. Doing it incorrectly could cause engine damage or even result in injury.

In short: If you’re unsure, don’t attempt the repair!

Will new spark plugs make my car run better?

New spark plugs won’t automatically make your car run better if there are other problems, but they can boost engine performance and fuel efficiency if your old ones are worn or damaged.

Other ways to keep your car performing well include keeping your tyres properly inflated and sticking to regular oil changes. Never skip your scheduled services!

Will replacing spark plugs improve acceleration?

Yes and no. Replacing worn or damaged spark plugs can help restore engine efficiency, which may improve acceleration.

However, new spark plugs won’t increase speed beyond your car’s capabilities. They simply ensure the engine runs smoothly and responds better when you press the accelerator.

Can I drive with a bad spark plug?

You can technically drive with a faulty spark plug, but it’s not recommended.

A bad plug can cause misfires and reduced engine power and put extra strain on the vehicle, potentially leading to costly repairs or danger on the road if left unaddressed.

Last thoughts

Spark plug replacement is an important part of routine car maintenance that can boost engine performance and improve fuel efficiency. It also helps to prevent costly repairs down the line.

So, although the spark plug replacement cost can sometimes be off-putting, it’s worth facing to save your wallet stress in the future!

Split the cost with Bumper

A repair fee is the last thing you want to have to deal with, but essential parts like spark plugs are key for a safe drive.

With Bumper’s car repair loan, you can split the cost of repairs into monthly payments at no extra cost.

Apply online for up to £5,000 and choose from 1,000s of trusted repairers.