Is your engine feeling sluggish? Noticed a dip in fuel economy or a harder time starting? These can be signs your spark plugs are overdue for replacement. Understanding the average spark plug replacement cost can help you stay ahead of repairs and budget for this essential maintenance.
But how much are spark plugs? They usually cost $5 to $25 each, and most cars need one per cylinder. Most modern vehicles have four to eight cylinders, so part costs can add up quickly.
When you include labor, the total price for a complete spark plug replacement typically falls between $100 and $250, though it can exceed $500 for larger engines or dealership work. Staying aware of common car problems and replacing spark plugs on schedule can help you avoid unexpected repairs down the road.
Factors Impacting Spark Plug Replacement Cost
Total replacement costs can vary significantly due to various factors, including spark plug composition, engine size and labor costs. Understanding what drives these differences can help you plan your budget and avoid surprises when it's time for a replacement.
Spark Plug Composition
What your spark plugs are made of greatly impacts both price and longevity. Standard copper spark plugs are often the least expensive option, but they wear out faster. On the other hand, premium materials like platinum and iridium cost more up front but can last much longer, making them a smart investment for many drivers.
Choosing the right type of spark plug depends on your vehicle's engine design and how often you want to service it. If you're unsure which is best, check your owner's manual or consult a trusted mechanic before you buy new plugs. Understanding auto parts prices can help you avoid overpaying for materials you don't actually need.
Here are the most common types of spark plugs and what sets them apart:
| Type | Cost | Lifespan | Other Notes |
| Copper | $2-$5 | 20,000-30,000 miles | Good conductivity for older vehicles |
| Single Platinum | $6€“$12 | Up to 60,000 miles | Resists wear better than copper |
| Double Platinum | $10€“$18 | 60,000€“100,000 miles | Platinum on both electrodes; used in older distributor-based ignition systems |
| Single Iridium | $12€“$20 | Up to 100,000 miles | Excellent durability for modern engines |
| Double Iridium | $16€“$25 | Up to 120,000 miles | Iridium on both electrodes; ideal for coil-on-plug systems |
| Ruthenium | $18€“$28 | 100,000€“120,000+ miles | Newer technology; not widely available |
| Silver | $8€“$15 | 15,000€“30,000 miles | Extremely rare, excellent conductivity; used in performance vehicles; less durable |
When it comes to spark plugs' cost, consider not just the price tag, but also how long each type will last before needing replacement. Installing the correct type recommended for your vehicle is essential, as using the wrong plug can affect engine performance, fuel efficiency and long-term reliability.
Engine Cylinder Size
The size of your engine and the number of cylinders it has play a significant role in determining the overall cost of a spark plug replacement. Engines with more cylinders require more spark plugs, so you'll pay more for both parts and labor.
For example, a four-cylinder engine might cost around $100 to $250 for parts and labor. For a V6, expect to pay between $150 and $350, and for a V8, the cost can range from $200 to $500 or more, especially if the plugs are hard to access or premium parts are required.
Before scheduling service, ask your mechanic for an estimate based on your engine's specific configuration so you know what to budget.
Labor Cost vs. DIY
Labor can be the biggest factor in the cost to replace spark plugs, with prices ranging from $40 to $150 per hour. While the allure of saving money with a DIY spark plug change is appealing, the reality of modern engines can make the job more complex than it seems. Choosing a professional ensures the work is done correctly and protects your engine from damage.
Trained technicians have the tools and experience to complete the job efficiently and correctly. They can also identify underlying issues , like oil leaks, misfires or ignition coil problems , contributing to spark plug wear. Visiting a AAA-approved auto repair facility gives you the benefit of trained technicians and warranty-backed service.
If you're comfortable tackling a spark plug change on your own, here are some basic steps to follow, along with a few important cautions to prevent costly engine damage:
- Refer to your vehicle's owner's manual and the spark plug manufacturer's instructions.
- Disconnect the negative battery terminal to prevent accidental electric shock.
- Make sure the engine is completely cool before starting.
- Remove any necessary engine covers to access the spark plugs.
- Use a spark plug socket and extension to loosen each plug carefully.
- Check the gap on new plugs to match your vehicle specifications. (Note: Many iridium and platinum spark plugs come pre-gapped and should not be adjusted.)
- Thread each new plug by hand first to avoid cross-threading.
- Tighten with a torque wrench to the manufacturer's recommended specs, over-tightening or under-tightening can damage the engine.
- Reattach any engine components and covers you removed.
If you're unsure, a certified mechanic can help you avoid costly mistakes and make sure your car runs at its best.
Signs to Replace Your Spark Plugs
Spark plugs are small but critical parts of your ignition system. They create the electrical spark that ignites the fuel and air in your engine's cylinders, producing power to keep you moving. Over time, the electrode wears down, which can cause starting problems, rough idling and other issues.
Here are some common symptoms that it's time for a replacement:
- Difficulty starting your car, especially in cold weather. Worn spark plugs are one of the common reasons your car won't start.
- Rough idling or unusual vibrations when your engine is running.
- Engine misfires, which can trigger a check engine light.
- Poor fuel economy or a noticeable drop in mileage.
- Sluggish acceleration or hesitation when pressing the gas pedal.
- Unusual noises, like rattling or popping from the engine.
Use Your AAA Membership to Save on Spark Plug Replacement Costs
Understanding your spark plug replacement cost can help you plan ahead and avoid unexpected repair bills. Whether you handle the work yourself or trust a professional, staying on top of maintenance protects your vehicle's performance. But if you find yourself stranded with a worn-out spark plug, AAA's Roadside Assistance can get you back on the road quickly.
Your AAA membership also gives you access to trusted repair facilities and member discounts that can make car care more affordable. From emergency tows to scheduled service, you have support whenever you need it. Learn more about AAA membership and see how it can help you save time and money on your next repair.
Spark Plug Replacement Cost FAQs
If you still have questions about spark plugs, here are answers to some of the most common concerns.
How often do spark plugs need to be replaced?
Most spark plugs last anywhere from 20,000 to 100,000 miles, depending on their material and your driving habits. Copper plugs wear out the fastest, while iridium and platinum plugs can go much longer before needing replacement. Always check your owner's manual or use a car maintenance checklist to track service intervals and stay ahead of repairs.
It's a good idea to inspect spark plugs regularly, especially if you notice symptoms like misfires, poor fuel economy or slow starts. Replacing them on schedule keeps your engine running smoothly and helps prevent damage to ignition coils or other components.
Why are spark plugs important?
Spark plugs do more than just start your engine , they help keep it running cleanly and efficiently every time you drive. Igniting the air and fuel mixture inside each cylinder creates the controlled combustion needed for smooth acceleration and reliable performance.
Replacing spark plugs on time helps you avoid performance issues. If spark plugs are worn or fouled, your vehicle may struggle to start, use more fuel or emit higher levels of pollutants. You can also experience problems such as hesitation when accelerating or reduced towing power.
When spark plugs are in good condition, your engine produces optimal power and consistent strength in all driving conditions. Over the life of your vehicle, keeping the ignition system in good shape can result in noticeable savings on fuel and maintenance.
What can happen if spark plugs aren't installed correctly?
Improper installation can cause serious engine problems and lead to expensive repairs. A cross-threaded or over-tightened spark plug can damage the cylinder head, creating a poor seal or causing the plug to break off. Under-tightening can also be risky, allowing combustion gases to leak past the plug.
Incorrect gaps or the wrong type of spark plug can result in misfires, rough idling and even engine damage over time. To avoid these issues, always follow the manufacturer's specifications and consider professional installation if you're unsure.
If you decide to replace spark plugs yourself, take your time and double-check every step to protect your engine and avoid extra costs.