Every car needs a spark to start. While the engine is a great force in helping a car start, it needs the spark from the spark plugs. For an internal combustion engine, the spark plugs help ignite the air-fuel mixture in the combustion chamber to start a car.
While spark plugs may sometimes wear out prematurely, they are also not built to last forever. Either way, you may need to replace them to keep up with engine performance. So how much does it cost to replace spark plugs?
Spark Plug Replacement Cost
The cost for replacing spark plugs ranges from $40-$260 depending on the type of spark plug, how many plugs are needed, and whether labor is on you or a mechanic. Here is a breakdown.
The cost of the plug as it relates to quality
Different types of spark plugs are built for different vehicles. There are the standard spark plugs, silver spark plugs, platinum, and iridium spark plugs. Platinum and iridium are built to last longer, so they are more expensive.
Standard spark plugs can be anywhere between $2- $10 per plug.
Similarly, you can get a single silver spark plug for around $5. One platinum spark is sold for around $4-$10, while a single iridium spark plug sells for around $6-$17.
Going for packs is even cheaper. You can even get a pack of 4 iridium spark plugs for between $24-$50. A pack of 4 platinum spark plugs is around $16-$24. And a Pack of 4 silver spark plugs between $11-$18.
While you may be tempted to opt for spark plugs built to last longer, they may not be a good fit for your specific car model.
Please refer to your owner’s manual on which type of spark plug is appropriate for your car.
The cost of spark plugs as it relates to how many you need
We have previously stated the cost of one spark plug. So the total amount you spend buying the plugs depends on how many you need. In the same vein, the number of plugs you need depends primarily on the type of engine and whether you’re changing all of them.
A six-cylinder engine will usually require more spark plugs than a four-cylinder engine.
For example, a V6 engine will require six plugs if each cylinder needs a single plug and 12 spark plugs if each cylinder needs two spark plugs. And vice versa for a V4 engine.
So if your car uses a platinum spark costing $10 per plug, you are expected to spend between $60 and $120 respectively for the plugs. So consult your owner’s manual to know the number of cylinders your car uses and how many plugs per cylinder are needed.
Another thing that influences spark plug replacement cost is the labor. If you’re doing it yourself, you only need to buy the plugs. Fixing spark plugs isn’t a complicated task; just ensure you have the knowledge and right tools needed for the job.
If you take it to an auto repair shop, you may spend $40-$158 for labor. However, labor cost also depends largely on your engine type. Fixing a spark plug is much easier for a four-cylinder engine, so the labor cost could be on the low spectrum, anywhere around $40-$100.
However, for a V6 engine, an auto repair shop may charge you as high as $126-$158 since the mechanic would need to take out the intake manifold to access the faulty spark plugs.
While replacing the spark plugs, it is also recommended to replace the air filters, fuel filters, O2 sensors and spark plug wires. These components, when faulty cam damage the new spark plugs.
Symptoms of a Bad Spark Plug
While it is always recommended that you follow your manufacturer’s interval for replacing spark plugs, they may wear out before then. Here are bad spark symptoms to look out for so you can take action early.
- Loss of power from your steering can cause your car to stop abruptly
- Engine misfire
- Reduced fuel efficiency
- Unexplained engine vibration leads to a shaky ride
- Rough idle
- Rough acceleration
- Illumination of the engine check light
Note: while the above often suggests a failing spark plug, other issues might be the culprit. The first step to determining if those symptoms stem from a bad spark plug is to note the last time you replaced the plugs. Spark plugs should last over 30k miles, so unless you have improperly installed them, the symptoms could point to other components.
Sometimes, those symptoms may stem from a bad ignition coil. However, to quickly diagnose if the spark plugs are the issue or other components, scan for trouble codes using any diagnostic tool. The diagnostic trouble codes will easily tell you why your car is acting that way.
How to Replace Spark Plugs
To replace the plugs, you will need the following tools
- Spark plug swivel socket with extension
- Flexible handle ratchet
- Spark plug wire puller
- Spark plug gap gauge
- Torque wrench.
To replace the spark plugs
- Park your car on a flat surface
- Clean the engine and spark plug cap surrounding to prevent dirt from falling into the cylinder when replacing the plugs.
- Disconnect the negative battery terminals. On no account should the negative or positive terminal touch any metal
- Remove the spark plug wires
- Remove the ignition coil on the plug
- Unscrew the spark plugs using a spark plug socket
- Install the new spark plugs
- Reinstall the spark plug wires or ignition coil
- Start the engine to be sure your car is functioning well
Note: If the valve gasket cover is leaking, it will let the oil come in contact with the spark plug coils and wire.
In this case, you will need to replace the valve gasket cover together with the spark plugs, spark plugs, wires, and coils. Here is a video detailing how to replace the spark plugs.
Whether to change all the plugs depends on the circumstances. If one spark fails prematurely, you can replace only that spark plug. However, if one plug fails near the end of its life expectancy, you should replace all the spark plugs. But ideally, replacing all spark plugs at once will keep all of them at the same performance level. Secondly, you won’t have to be replacing them at different intervals. For an appropriate spark plug maintenance schedule, please consult your owner’s manual.
Spark plugs should be replaced between 30k-120k miles depending on the spark plug type and how much you maintain them. Ideally, conventional spark plugs should be replaced every 30k-40k miles. Iridium spark plugs can be replaced after 60k miles.
However, extended-life spark plugs can be replaced every 100k-120k miles. Better still, follow the recommended interval in your owner’s manual.
Spark Plugs can be replaced by individuals or taken to a mechanic. Spark plug replacement isn’t a complicated job, so you can do it if you have the right tools. It will help you save costs. If, however, you don’t have the mechanical knowledge and right tools, please reach out to a mechanic for spark plug repair services.
While there are different types of spark plugs, it’s not one type fits all. You may be tempted to go for a high-end plug so that you can use it for long; no, it doesn’t work that way. Which spark plug fits and works well for your car depends on the one recommended by your vehicle manufacturer. Please refer to your owner’s manual to get the correct spark plugs for your model.
Very old spark plugs may cause engine damage, but worn spark plugs will usually reduce engine performance. Ideally, if you fail to replace spark plugs at the recommended intervals, you will experience rough idling, engine misfire, and decreased fuel economy. Wait too long; you may experience power loss that can keep you stranded on the road.
Spark Plug replacement cost is usually inexpensive and an easy job. To keep up with engine performance, avoid engine damage and costly repairs, and replace them on time.
Once they have lived up to their life expectancy or you notice some bad spark symptoms listed above, have them replaced immediately.
Ideally, you can have it done at an auto repair shop for around $40-$260. Or you can save cost doing it yourself if you have the right tools and knowledge.
Also, remember it’s essential to replace other components such as the air filter, spark plug wires, and serpentine belt. Also, clean or replace the mass airflow sensor. If either of them is faulty, they will soon damage the new spark plugs.