How Much Does A Spark Plug Replacement Cost in the UK?

Spark plugs are one of the most important parts of the ignition system of a petrol engine vehicle. They create the spark that ignites the air/fuel mixture in the engine, which in turn powers your car.

The purpose of a spark plug is to deliver an electrical spark to the combustion chamber of an engine to ignite the fuel. Spark plugs are typically made of metal/ceramic and have a threaded portion that screws into the engine. Over time, spark plugs can become fouled, damaged or worn, which can cause engine misfires, hard starts, and decreased fuel economy.

How much does it cost to replace spark plugs?

The average cost of replacing a set of spark plugs is £85, with prices ranging from £55 and £125. Furthermore, the number of spark plugs required and the type of spark plug needed for your vehicle will be a cost factor to consider. Many newer cars have iridium spark plugs, which are more expensive but have a longer service life than traditional spark plugs. The exact price of the spark plug replacement depends largely on your car and the parts recommended by the manufacturer. Your location can also be a key factor in determining the price of a spark plug change. For example, average hourly labour rates and demand in cities like London is around £50-£100 while in towns with lower demand, the labour rates can range from £35-£50. The type of mechanic, for example, a mobile mechanic vs a dealership garage technician can also affect the total cost of spark plug change.

Average cost of a spark plug replacement by location

To avoid having car owners overpaying and get a fair price for spark plug change, we use real-time data of thousands of car makes and model data, local labour prices for spark plug replacements and part prices to provide an instant fair quote. Simply enter your vehicle registration number and postcode to get an instant price for a spark plug replacement for your car.

Average cost of a spark plug replacement by manufacturer

Signs your spark plugs need to be replaced

• Noisy engine or rough idling
• Decrease in fuel efficiency
• Loss of engine power or frequent misfires

Excessive vibrations

Along with rough idling if there is excessive noise from the engine bay, then it could indicate an issue with the spark plugs.

Increased emissions

Faulty spark plugs can cause an increase in emissions because they can cause the engine to not ignite the fuel correctly and then run less efficiently. This is usually accompanied by an increase in fuel consumption.

The engine misfires

An engine misfire is when the air-fuel mixture in the cylinders fails to ignite. This can be caused by a number of things, including a faulty spark plug. A misfire can sound like a clicking, sputtering or coughing sound and can be felt as a jerk or roughness while driving.

Trouble starting the car

If any one of the spark plugs is faulty, it will cause trouble starting a car because the spark plug is responsible for igniting the air/fuel mixture in the engine. If the car fails to start completely it could indicate an issue with the wiring or a flat battery.

Frequently asked questions about spark plug replacement cost

Are spark plugs worth changing?

Yes, spark plugs are worth changing when they are no longer firing correctly. Over time, spark plugs can become corroded or fouled, which can cause them to misfire. When this happens, it can cause your engine to run less efficiently and can even damage the catalytic converter and other parts of the engine.

What happens after changing spark plugs?

The spark plugs are changed in order to improve the performance of the engine. After changing the spark plugs, the engine will be able to start more easily and will run more smoothly. New spark plugs will also increase fuel efficiency to some extent.

Do I need to replace all spark plugs at the same time?

It is recommended that all spark plugs are changed at the same time to avoid uneven wear and stains on the ignition coil. Over time, spark plugs can wear down and become less effective, so replacing them all at once can ensure they have the same level of electrical resistance which helps overall engine performance.

How long does spark plug change take?

On average a spark plug change will usually take 1 hour for an average UK passenger car, but can take anywhere from under 1 hour to 1.5 hours. The time that the job takes will depend on a range of factors. For example, your vehicle's make and model, year, as well as other factors. Select your car at the top of this page for information on job time and cost for your vehicle through ClickMechanic.

Can I carry out a spark plug change myself?

Removing the old and installing new spark plugs does require some basic automotive knowledge and skills. Furthermore, if the spark plugs are seized and are “stuck” on the cylinder head then it requires special attention so as to not snap a spark plug and cause further damage to other parts.
Unless you are a qualified mechanic with the required skills, training and equipment to do the job, we strongly recommend a spark plug change is only carried out by a professional mechanic. ClickMechanic can help get you a vetted and local mechanic to carry out the work. Just enter your postcode and your car's registration number at the top of this page and select the work needed to get an instant fixed price upfront.

What happens during a spark plug change or replacement?

• Mechanic will read the ECU for possible fault codes related to the ignition system.
• Mechanic will inspect the ignition system and spark plugs.
• If necessary, the mechanic will replace the full set of spark plugs
• Mechanic will advise if any other parts need to be replaced.
• Mechanic will check if the ignition system works correctly again and will test drive the car.