How To Change Spark Plugs 2012 Honda Civic?

Spark plugs are crucial components in your Civic ignition system. Over time, they can become dirty or worn out, resulting in misfires, reduced power, poor acceleration, and increased fuel consumption. Replacing them every 30,000 to 100,000 miles will restore engine performance and gas mileage.

In most cases, you can change spark plugs 2012 Honda Civic yourself in under an hour with basic tools. This article provides detailed instructions for locating, removing, and installing new spark plugs, along with tips for proper gapping and torque specs. Read on to learn everything you need to know to safely and efficiently change spark plugs on your 2012 Honda Civic.

What You’ll Need

Before beginning the spark plug replacement process, you’ll need to gather the following tools and parts:

  1. Socket wrench and extensions
  2. Spark plug socket (5/8 inch or 16mm)
  3. Anti-seize compound
  4. Clean rags
  5. Flashlight
  6. Replacement spark plugs – consult your owner’s manual for the correct type
  7. Optional: torque wrench, feeler gauges, spark plug gap tool

Be sure you have the right spark plugs for your Civic’s make, model, and engine. Using the wrong type of plugs can cause performance issues. OEM Honda plugs or equivalent aftermarket plugs are recommended.

Step 1 – Disconnect The Battery

The first step is to disconnect your Civic’s battery. This cuts power to the ignition system and avoids the risk of electrical shock while working:

  1. Locate the battery in the engine bay. It will have a red positive (+) terminal cover.
  2. Using a wrench, loosen the nut on the negative (-) black terminal clamp.
  3. Detach the clamp from the terminal to disconnect the battery.
Change The Spark Plugs 2012 Honda Civic
Change The Spark Plugs 2012 Honda Civic

Tip: Avoid touching the positive and negative terminals together while the battery is disconnected to prevent sparks.

Step 2 – Access The Spark Plugs

On Civics, the spark plugs are located deep in the engine bay and are not easily reachable. You will need to remove some components to gain access:

Remove Engine Cover

  1. Locate the plastic engine cover. It will have Honda lettering on top.
  2. Loosen any fastener clips or bolts securing the cover.
  3. Lift it straight up and off the engine to remove.

Remove Ignition Coils

The ignition coils attach over the top of each spark plug and deliver the high voltage current.

  1. Clean any dirt or debris from around the ignition coil boots.
  2. Disconnect the wiring harness from each coil by squeezing the clip and pulling firmly.
  3. Remove the single bolt securing each coil using a socket wrench.
  4. Lift the coils straight up to remove them.

Tip: Label the coils based on cylinder number using tape to simplify reinstallation.

Step 3 – Remove The Old Spark Plugs

With the coils out of the way, you can now access the spark plugs themselves:

  1. Use your spark plug socket and a socket wrench/extension to loosen each plug. Turn counterclockwise to loosen.
  2. Carefully pull the old plugs out of the cylinder head. Be careful not to damage the porcelain insulator.

Tip: Be prepared for some oil residue around the plugs – this is normal. Use rags to contain any leaks.

Step 4 – Inspect The Old Plugs

Before installing the new plugs, closely inspect the old ones for signs of damage or abnormal wear patterns:

  1. Look for cracks in the insulator around the electrodes which indicate it’s time for replacement.
  2. Check that the ground electrode (curved) and center electrode are not badly eroded or corroded. Minor erosion is normal over time.
  3. Measure the existing gap on the plug using a feeler gauge tool. Compare to the new plug gap spec below.

This visual inspection can provide clues to issues like oil leaks, combustion problems, or improper spark plug maintenance intervals.

Step 5 – Set The Spark Plug Gap

Before installing new spark plugs, their gap must be set to the proper spec:

  1. Use a spark plug gap tool to set the space between the ground and center electrodes to 0.8-0.9 mm (0.031-0.035 inches).

Adjust the gap carefully by bending only the ground electrode. Wider gaps can cause misfires while narrow gaps increase resistance. The gap on new plugs may differ slightly from the ideal spec.

Step 6 – Apply Anti-Seize Compound

Before inserting new plugs, add a small amount of anti-seize lubricant to the threads:

  1. Put a thin coat on the upper thread portion to prevent the plug from sticking. Make sure the electrodes remain clean.
  2. This makes future spark plug removal much easier and prevents damage to the cylinder head threads.

Step 7 – Install New Spark Plugs

You’re now ready to install the new plugs into the cylinder head:

  1. Hand thread each new plug a few turns to get it started avoiding cross-threading.
  2. Use your socket wrench to tighten the plug to the proper torque spec of 15 to 21 ft-lbs. Overtightening can damage the threads.
  3. Reinstall the ignition coils and wiring in reverse order of removal. Ensure the boots snap securely onto the plugs.
  4. Replace the engine cover and reconnect the battery when complete.
Change Spark Plugs 2012 Honda Civic
Change Spark Plugs 2012 Honda Civic

Double check that all plugs are properly tightened before starting the engine.

Step 8 – Start The Engine

The final step is to start the engine and check for any ignition issues:

  1. Turn the key and let the engine run for a minute. Listen for any misfires or roughness that may indicate a problem.
  2. With the engine warmed up, rev it to 2,500-3,000 RPM and check for any hesitation or power loss that could signal faulty installation.
  3. Turn the engine off and allow the exhaust to cool down. Inspect all spark plug wires and boots again for proper attachment.

If everything checks out, the new plugs are working as they should! Be sure to keep an eye on your Honda’s performance over the next few drives.

How Often Should You Change Spark Plugs On A 2012 Honda Civic?

Honda recommends changing the spark plugs on a 2012 Civic every 100,000 miles or 7 years, whichever comes first. However, driving habits and conditions can impact the ideal replacement interval. 

More frequent changes may be needed if you drive mostly short trips, in stop-and-go traffic, or in very hot or cold weather. Sticking to the manufacturer’s recommendations helps keep your Civic’s ignition system in optimal condition.

How Much Does It Cost To Change Spark Plugs On A 2012 Honda Civic?

The average cost for a 2012 Honda Civic spark plug replacement ranges from $150-200. This covers parts and labor costs. The plugs themselves cost around $8-15 each, with Civics requiring 4 plugs. You’ll also incur shop fees of around $50 per hour for installation labor time. 

Additional taxes and service charges can add $20 or more to the final bill. Changing them yourself can save on labor costs, but requires more time and mechanical skill.

How Many Spark Plugs Does A 2012 Honda Civic Have?

The 2012 Honda Civic has a 4-cylinder engine, which means there are 4 spark plugs. One plug serves each of the 4 combustion chambers in the engine. V6 engines will have 6 plugs, while inline 4-cylinder motors like the Civic have just the 4. 

Knowing the number of plugs allows you to purchase the correct quantity for a complete replacement job.

What Is The Spark Plug Gap On A 2012 Honda Civic?

The recommended spark plug gap spec for a 2012 Honda Civic is 0.8-0.9 mm or 0.031-0.035 inches. This refers to the space between the ground and center electrodes on the plug. A gap in this range provides an optimal spark for combustion. The gap on new replacement plugs should be checked and adjusted as needed to the spec before installation.

How Do I Check My Spark Plug Gap?

You can check the gap on a spark plug using a feeler gauge tool. This is a set of thin metal blades with precise thicknesses. Insert various blades between the electrodes until one fits snugly – that blade’s thickness indicates your plug gap. Compare to your vehicle’s spec in the manual and adjust if needed by bending the ground electrode carefully.

What Is The Correct Spark Plug Gap?

The correct spark plug gap depends on your specific vehicle make and model. Gaps generally range from 0.6 to 1.1 mm. Consult your owner’s manual to find the exact plug gap spec recommended by the manufacturer. For a 2012 Honda Civic, the ideal gap is 0.8-0.9 mm or 0.031-0.035 inches. Matching this spec optimizes ignition performance.

Faqs And Troubleshooting

How Often Should Plugs Be Replaced?

Honda recommends replacing the spark plugs every 100,000 miles or 7 years. However, the actual interval depends on your driving habits and conditions. More frequent replacement may be needed for short trips, stop-and-go traffic, or very hot/cold weather driving.

Why Is Proper Torque Important?

Torquing the spark plugs to the factory spec ensures adequate sealing without putting excess strain on the threads. Overtightening can damage the cylinder head or even crack the porcelain on plugs.

What’s Causing Difficulty Removing Plugs?

Rust, corrosion, and carbon deposits can make the plugs hard to remove over time. Allowing oil to leak past worn engine seals can also cause this issue. Using anti-seize lubricant on the threads makes future removal much easier.

My Civic Is Having Ignition Issues After Replacement

Double check all coils and plug wires are properly connected. Ensure the new plugs have the correct heat range and gap spec. In rare cases, a defective new plug can happen – try swapping locations to isolate the problem cylinder.


While spark plug replacement may seem intimidating, this guide has shown that any DIYer can learn how to change spark plugs on a 2012 Honda Civic with basic tools and proper precautions. Sticking to the step-by-step process outlined above along with the recommended maintenance intervals will keep your Civic’s ignition system in optimal condition.

Feel free to refer back to the instructions above if you need a refresher down the road. With practice, you’ll gain confidence replacing your Honda’s spark plugs and be able to restore engine performance easily when needed.

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Ammar Masoud

I have had a long and fulfilling career in the automotive industry, primarily with Honda and Acura. With 15 years of experience as a Honda service technician, I became highly skilled in repair and maintenance, gaining a deep understanding of these vehicles. After many years in the automotive field, I decided to embark on a second career in industrial manufacturing. It was a significant change, but I found that the skills I had honed in the automotive industry were incredibly valuable in my new role. In my current position in industrial manufacturing, the demand for quality workmanship and meticulous attention to detail is paramount. Fortunately, these are traits that I have cultivated throughout my years in the automotive industry. I take pride in applying these skills to meet the high standards expected in the manufacturing sector.