A Guide to Spark Plugs for the 2018-2021 Honda Clarity Plug-In Hybrid
Keep your Clarity's unique 1.5L hybrid engine running smoothly by understanding when to replace your spark plugs and which ones to choose.
- The recommended replacement is the OEM-equivalent NGK Laser Iridium spark plug (DILZKAR7C11H).
- Your car's Maintenance Minder system will tell you when to change the plugs by displaying service code '4'.
- Replacement is a simple DIY job that can be done in under an hour with basic tools.
- Be aware that engine stalling could be related to a fuel pump recall on 2018-2019 models, not necessarily the spark plugs.
Signs of Failing Spark Plugs
Because the Clarity's gasoline engine doesn't run all the time, symptoms of a bad spark plug might seem intermittent. Pay attention to how the car behaves when the gas engine kicks in. Worn plugs can't create a strong enough spark, leading to incomplete combustion.
- Rough Idle: When the gasoline engine is running, you may feel excessive vibration or shaking while stopped.
- Engine Hesitation: During acceleration, the car may stumble or lack power when the gas engine is engaged.
- Reduced Fuel Economy: If you notice you're getting fewer miles per gallon, failing spark plugs could be a cause, as the engine works harder to compensate for poor combustion.
- Check Engine Light: A misfire will almost always trigger the check engine light. Common codes include P0300 (random/multiple misfire) or P0301-P0304 (indicating a misfire in a specific cylinder).
Important Note on a Related Issue
The 2018-2019 Honda Clarity was subject to a major safety recall for a faulty fuel pump that could cause the engine to stall while driving. Symptoms like engine hesitation or stalling can overlap with severe spark plug failure. If you experience these issues, it is crucial to check if your vehicle's VIN is part of the recall by checking the NHTSA website.
Choosing the Right Aftermarket Spark Plugs
When replacing spark plugs on your Clarity, you have a choice between OEM and aftermarket parts. However, for this vehicle, the choice is straightforward.
OEM vs. Aftermarket Quality
The original factory spark plugs for the 2018-2021 Clarity are made by NGK. They are high-quality Iridium plugs designed for longevity and performance in your specific engine. When buying aftermarket, choosing the NGK-branded equivalent gives you the same part without the Honda dealership markup. Forum members and Honda specialists consistently recommend sticking with NGK for Honda engines to ensure compatibility and avoid potential issues.
Brand Recommendations
- Tier 1 (OEM): NGK
The OEM part is an NGK Laser Iridium plug, specifically model DILZKAR7C11H (stock number 95815). This is the best and most recommended choice. These plugs are designed to meet the precise requirements of the Clarity's 1.5L engine. 🎬 See how to access the plugs on this 1.5L engine.
- Tier 2 (High-Quality Aftermarket): Bosch
Bosch also produces high-quality Double Iridium spark plugs that are compatible with the Clarity. While Bosch is a top-tier brand, especially for European vehicles, the general consensus in the Honda community is to prefer NGK, the original supplier.
Pro Tip: Always replace spark plugs as a full set of four. This ensures even performance and wear across all cylinders. Since you already have the engine cover off, replacing all of them at once saves you from having to do the same job again in the near future.
Cost of Replacing Spark Plugs
The cost can vary depending on whether you do the job yourself or take it to a shop. The replacement is a simple DIY task for those with basic tools.
| Item | Cost Range |
|---|---|
| New Aftermarket Spark Plugs (Set of 4) | $62 - $120 |
| New OEM Spark Plugs (Set of 4) | $110 - $160 |
| Shop Labor | $100 - $150 |
| Total Professional Replacement | $172 - $270+ |
Frequently Asked Questions (FAQ)
When should I replace the spark plugs on my Clarity?
Your Clarity uses Honda's Maintenance Minder system. It will display a service code '4' on the dashboard when it's time to replace the spark plugs. There is no fixed mileage interval; the car's computer determines the timing based on engine usage. One owner reported replacing them after an estimated 85,000-95,000 miles of engine run time.
Do I need to use anti-seize on the new spark plug threads?
No. NGK spark plugs, including the OEM ones for your Clarity, have a special trivalent plating that acts as its own anti-seize and prevents corrosion. Adding extra anti-seize can lead to over-torquing the plugs, which can damage the threads in the aluminum cylinder head.
Why are Iridium spark plugs recommended?
Iridium is an extremely hard and durable precious metal. Using it for the spark plug's fine-wire center electrode allows for a more focused and consistent spark, improving ignition efficiency and engine performance. It also gives them a very long service life, which is why they are used as original equipment in modern engines like the one in your Clarity.
Is it difficult to replace the spark plugs myself?
No, this is a very simple job. It involves removing the plastic engine cover, unplugging the four ignition coils, removing one bolt per coil, and then using a 14mm spark plug socket with an extension to remove and replace the plugs. The entire process can be done in under an hour with basic hand tools.
🎬 Watch this step-by-step guide to replacing your Clarity's spark plugs.Helpful Videos
Technical Specifications
OEM Part Numbers: 12290-5WJ-A01
The OEM spark plug is an NGK Laser Iridium plug, model DILZKAR7C11H. The engine requires a set of four plugs. A 14mm spark plug socket is needed for installation.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
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