How Much to Replace Spark Plugs: Cost Breakdown and Tips

Here’s a table estimating the cost to replace iridium spark plugs for four, six, and eight-cylinder engines.

The costs can vary depending on the vehicle model, location, and service provider, but the table provides a general idea.

This plug was pulled with no check engine light on, but was causing a noticeable drop in MPG
Engine TypeAverage Cost per Spark PlugTotal Cost Range (Including Labor)
4-Cylinder$15 – $25$100 – $200
6-Cylinder$15 – $25$150 – $300
8-Cylinder$15 – $25$200 – $400


  • Average Cost per Spark Plug: This is the usual cost for one iridium spark plug, which can be higher for some specific car models.
  • Total Cost Range: Includes the cost of all spark plugs and the labor for installation. Labor costs can vary significantly based on the complexity of the engine and the rates charged by the service shop.

These costs are approximate and can vary based on factors like geographical location and specific vehicle model details. It’s a good idea to check with local mechanics or dealerships for a precise quote.

Why Replace Spark Plugs Regurarly

Spark plugs are a critical component in your vehicle’s ignition system, facilitating the combustion needed to start and run your engine.

Over time, spark plugs can degrade, leading to various engine problems. It is important for you to replace them periodically to maintain optimal engine performance and fuel efficiency.

Notable benefits of replacing spark plugs include:

  • Improved Fuel Economy: Worn spark plugs can reduce fuel efficiency. When they are replaced, you often notice an improvement in miles per gallon.
  • Consistent Combustion: New spark plugs ensure reliable engine start-ups and a smoother running engine.
  • Reduced Emissions: By ensuring complete combustion, fresh spark plugs can help lower your car’s emissions.

The typical signs that you may need new spark plugs include:

  • Engine misfires
  • Rough idling
  • Difficulty starting your vehicle
  • Noticeable lack of acceleration

Routine maintenance schedules suggest spark plug replacement at regular intervals; these intervals vary by vehicle make and model, but a general guideline is every 30,000 to 90,000 miles. Check your owner’s manual for your vehicle’s specific needs.

When selecting spark plugs:

  1. Choose the right type for your vehicle (consult your manual or a professional).
  2. Consider performance requirements and whether you prefer long-life plugs.
  3. Evaluate the materials, such as copper, platinum, or iridium.

Replacing Spark Plugs: What Controls Cost

Count the plug wires to determine the amount of plugs in your V6. It’s almost always 6.

The price for replacing spark plugs can vary widely based on your vehicle’s specifications and the spark plugs you choose. Let’s examine the factors that shape this maintenance expense.

Vehicle Model and Engine Type

  • Your car’s make and model play a significant role in spark plug replacement costs.
  • Specific high-performance engines require more expensive spark plugs than standard vehicles.
  • Labor costs may increase for engines that are difficult to access or require additional time for installation.

Type of Spark Plugs Used

  • Standard Copper Spark Plugs are the most economical option but have a shorter lifespan.
    • Price Range: $2 – $5 per plug
  • Iridium and Platinum Spark Plugs offer better longevity and performance, which reflects in their price.
    • Price Range: $6 – $15 per plug
  • Specialty or Performance Spark Plugs can exceed the typical price range, especially for sports or luxury vehicles.
    • Price Range: May start around $15 and can be substantially higher per plug

How to Replace Spark Plugs

Before you begin, make sure your engine is cool to avoid injury.

Tools You’ll Need:

  • Spark plug socket
  • Socket wrench
  • Extension bar
  • Spark plug gap tool
  • New spark plugs

Step-by-Step Guide:

  1. Locate Your Spark Plugs:
    • Refer to your vehicle’s manual to find the spark plug location. Typically, they are attached to thick rubber wires.
  2. Remove the Spark Plug Wires:
    • Gently twist the spark plug wire boot to release it.
    • Pull the boot away from the spark plug (do not yank on the wires).
  3. Clean the Area:
    • Use a compressed air can or a brush to clean around the spark plug. This prevents debris from falling into the cylinder hole.
  4. Remove the Old Spark Plugs:
    • Use the spark plug socket and extension on your wrench to unscrew each plug.
    • Apply gradual pressure to loosen and remove the plug.
  5. Inspect and Prepare the New Spark Plugs:
    • Check the gap on new plugs using a gap tool, adjusting as needed.
    • Match them to the old ones to ensure they are the correct type and size.
  6. Install the New Spark Plugs:
    • Hand-thread the new plug into the cylinder head.
    • Tighten with the spark plug socket — be cautious to not overtighten.
  7. Reattach the Spark Plug Wires:
    • Press the wire boot onto the new spark plug until you feel it click into place.


  • Replace spark plugs one at a time to maintain the correct order.
  • Do not over-tighten the spark plugs, as this can damage the threads.

When to Replace Spark Plugs

Spark plugs play a critical role in your vehicle’s engine function, igniting the air/fuel mixture to start your car. The frequency of replacing spark plugs can vary depending on your vehicle type and the conditions under which you drive. Generally, consider the following guidelines:

  • Mileage: Check your owner’s manual for the manufacturer’s recommendation. Most suggest replacing spark plugs every 30,000 to 90,000 miles.
  • Performance Issues: If you notice a decline in fuel economy, irregular engine idling, or difficulty starting your car, your spark plugs may need attention.

Maintenance Schedule:

  • For standard copper spark plugs, inspect them every 20,000 to 30,000 miles.
  • For platinum or iridium spark plugs, they often last longer, potentially 60,000 to 100,000 miles.

Visibly Checking Spark Plugs:

  • Look for wear and tear or deposits.
  • Check for a worn electrode or damage to the insulator.

Other Considerations:

  • If your vehicle still has its original spark plugs after extensive use, it’s prudent to have them checked.
  • Consistent engine misfires could signal it’s time for a replacement.

Ways to Save on Spark Plug Replacement

Replacing your spark plugs can be a necessary maintenance task to keep your vehicle running smoothly.

The cost can add up, but with a few strategies, you can manage to save money on this service.

  • Perform Regular Checks: By regularly checking your spark plugs, you can identify issues early and avoid more costly repairs down the line.
  • Learn to DIY: If you’re comfortable with basic car maintenance, consider replacing your spark plugs yourself.
  • There are numerous tutorials available online to guide you through the process.
  • Shop for Deals: Keep an eagle eye on sales and promotions at auto parts stores. Sometimes you can find high-quality spark plugs at a lower cost.
  • Use Quality, Not Premium: Opt for good-quality spark plugs instead of the pricier premium options if your vehicle doesn’t require them.
  • This can save you money without compromising performance.
  • Bulk Purchases: Some retailers offer discounts when you buy spark plugs in bulk. This is particularly useful if you own multiple cars or a fleet.

To further ensure savings:

  • Compare Labor Costs: If you’re not doing it yourself, compare labor charges between local repair shops and dealerships. Independent shops often provide competitive rates.
  • Purchase Online: Often, online retailers offer parts at reduced prices compared to brick-and-mortar stores.
  • Make sure the seller is reputable to avoid counterfeit parts.
  • Join Rewards Programs: Auto parts stores often have rewards programs that offer discounts, coupons, or points you can redeem on future purchases.