Changing the spark plugs in your 2012 Honda Civic is a great way to maintain engine performance and fuel efficiency. This step-by-step DIY guide will show you exactly How To Change Spark Plugs 2012 Honda Civic safely and correctly.
With basic tools and about an hour of your time, you can complete this job yourself and save a significant amount on labor costs. It’s a straightforward process that any motivated car owner can handle.
How To Change Spark Plugs 2012 Honda Civic
Before you begin, it’s crucial to understand why this maintenance task matters. Worn spark plugs can cause rough idling, poor acceleration, reduced gas mileage, and even difficulty starting your car. Following this guide will help you avoid those issues.
What You’ll Need: Tools and Parts
Gathering everything before you start is the key to a smooth project. Here’s your checklist:
* New Spark Plugs: For the 2012 Civic, you need 4 plugs. Honda recommends NGK IZFR6K-11S laser iridium plugs. Double-check your owner’s manual or the under-hood sticker to confirm. Using the wrong type can cause problems.
* Socket Set: You will need a 3/8-inch drive ratchet, a 5/8-inch (16mm) spark plug socket, and a 6-inch extension. A magnetic plug socket is highly recommended.
* Gap Tool: While most iridium plugs come pre-gapped, you should always verify the gap. Use a wire-style gap gauge, not a coin-type, to avoid damaging the delicate electrode.
* Torque Wrench: This is essential for tightening the plugs to the exact specification without stripping the threads.
* Other Helpful Tools: A flat-head screwdriver, needle-nose pliers, and a small brush or compressed air for cleaning.
* Safety Gear: Safety glasses and nitrile gloves are smart choices.
Important Safety Precautions
Your safety and your car’s safety come first. Please follow these rules:
* Work on a Cold Engine: Never attempt to change spark plugs on a hot engine. Wait at least an hour after driving. The plugs and cylinder head can be extremely hot and cause serious burns.
* Disconnect the Battery: Always disconnect the negative (black) terminal of your battery before starting. This prevents any accidental electrical shorts.
* Clean Work Area: Keep dirt and debris away from the open spark plug holes. If anything falls into a cylinder, it can cause severe engine damage.
Step-by-Step Replacement Guide
Now, let’s get into the actual process. Follow these steps in order.
Step 1: Prepare Your Vehicle
Park your Civic on a level surface and engage the parking brake. Open the hood and locate the negative battery terminal. Use a 10mm wrench to loosen the nut and disconnect the cable, tucking it away from the battery post.
Step 2: Locate and Expose the Spark Plugs
The spark plugs on your 2012 Civic are located on the top of the engine, under the ignition coil assembly. You’ll see a long, black plastic piece running along the top of the engine with four electrical connectors and a 10mm bolt at each end.
Step 3: Remove the Ignition Coils
Start by disconnecting the electrical connector on each coil. Press down on the small locking tab and pull the connector straight off. Next, use your socket to remove the 10mm bolt securing each coil. Once the bolt is out, the coil can be gently pulled straight up and out of the valve cover. Sometimes they can be snug, a gentle twisting motion can help.
Place each coil in order on a clean surface so you know which cylinder it came from, though they are generally interchangeable.
Step 4: Remove the Old Spark Plugs
Before removing the first plug, use your compressed air or brush to clean any loose debris from around the plug well. This prevents anything from falling into the cylinder.
Insert your 5/8-inch spark plug socket with the extension into the first well. Attach your ratchet and turn it counterclockwise to loosen the plug. Once it’s loose, you can usually finish unscrewing it by hand. Carefully lift the socket and extension out, with the old plug securely inside. Repeat this process for the remaining three cylinders.
Step 5: Inspect and Gap the New Plugs
Lay out your old plugs and new plugs side-by-side. Compare them to ensure the new ones are the correct type and size. Even though they are pre-gapped, you must check.
Find the specified gap for your Civic, which is 0.039–0.043 inches (1.0–1.1 mm) for the recommended NGK plug. Carefully insert the wire gauge. If adjustment is needed, only bend the ground electrode (the L-shaped piece at the tip) very slightly. Never touch or bend the center electrode.
Step 6: Install the New Spark Plugs
This is the most critical step. Do not use your ratchet to tighten the plugs initially.
Start each new plug by threading it into the hole by hand. Turn it clockwise until it seats. If it feels gritty or binds, back it out and start again to avoid cross-threading. Once it’s hand-tight, it’s time for the torque wrench.
Attach your torque wrench to the extension and socket. The factory torque specification for the 2012 Honda Civic is 13 lb-ft (18 Nm). Tighten each plug smoothly to this setting. Over-tightening is a common mistake that can damage the cylinder head threads.
Step 7: Reinstall the Ignition Coils
Take each ignition coil and carefully insert it back into its respective tube, pushing down firmly until it seats completely on top of the spark plug. Reinstall the 10mm bolt for each coil and tighten it snugly, but don’t overtighten the plastic. Finally, reconnect each electrical connector until you hear a definitive click.
Step 8: Reconnect the Battery and Test
Go back to the battery and reconnect the negative terminal. Tighten the 10mm nut securely. Now, start your car. The engine may crank slightly longer than usual as the system re-initializes. It should then idle smoothly. Listen for any misfires or rough sounds. If everything sounds good, turn the engine off.
Troubleshooting Common Issues
Sometimes, things don’t go perfectly. Here’s what to watch for:
* Engine Misfire After Installation: Double-check that all coil connectors are fully clicked in. Ensure each coil is fully seated on the spark plug.
Cross-Threaded Spark Plug: If a plug wouldn’t thread in smoothly and you forced it, you may have damaged the threads. This will likely require a professional repair called a heli-coil insert.
* Broken Spark Plug: This is rare, but if an old plug breaks, you’ll need a specialized tool to extract the remaining piece from the cylinder head.
Maintenance Tips and Schedule
Honda recommends changing the spark plugs in the 2012 Civic every 105,000 miles under normal driving conditions. However, if you experience symptoms like hard starting or poor fuel economy earlier, it’s wise to check them.
Using the correct, high-quality iridium plugs ensures you get the full lifespan and performance. It’s also a good idea to inspect the ignition coil boots for any cracks or tears while they’re out.
Frequently Asked Questions (FAQ)
Q: How often should I change the spark plugs in my 2012 Honda Civic?
A: The official maintenance minder recommends replacement at around 105,000 miles. Severe driving conditions may require more frequent changes.
Q: Can I use cheaper copper spark plugs instead of iridium?
A: While they will physically fit, copper plugs have a much shorter lifespan (about 30,000 miles) and are not recommended for your Civic’s engine. Sticking with the OEM-specified iridium plug is best for performance and longevity.
Q: What happens if I don’t torque the spark plugs?
A: Under-tightening can lead to a poor seal, causing compression loss and overheating. Over-tightening can strip the aluminum threads in the cylinder head, leading to a very expensive repair.
Q: Is it okay to change just one or two spark plugs?
A: It’s always best to change all four spark plugs at the same time. This ensures even combustion and consistent performance across all cylinders. Mixing old and new plugs can lead to uneven engine wear.
Q: Why did my check engine light come on after I changed the plugs?
A: The most common reason is an unplugged or loose ignition coil connector. Recheck all four connections. If the light persists, you may need an OBD2 scanner to read the specific code, which could indicate a faulty coil or another issue.
By completing this job yourself, you’ve not only saved money but also gained valuable insight into maintaining your vehicle. Regular maintenance like this is key to keeping your 2012 Honda Civic running reliably for many more miles. Remember to dispose of your old spark plugs properly, as they are made of materials that shouldn’t just be tossed in the regular trash. Many auto parts stores offer recycling for them.