Spark Plug Replacement Guide for the 2004-2008 Honda Pilot
Keep your Pilot's V6 engine running smoothly by choosing the right spark plugs and avoiding common issues.
- The 2004-2008 Honda Passport does not exist; this guide is for the 2004-2008 Honda Pilot.
- Stick with OEM brands NGK or Denso for spark plugs to ensure proper performance and avoid issues.
- The three spark plugs at the rear of the engine are difficult to access, making the job more challenging than on other vehicles.
- Recurring spark plug fouling could be a sign of a more serious engine issue related to the piston rings, especially on 2006-2008 models with VCM.
Symptoms of Failing Spark Plugs
When spark plugs wear out, they can't create a strong enough spark. This leads to an incomplete fuel burn, a condition called a 'misfire.' You will likely notice one or more of these signs:
- Check Engine Light: A failing spark plug is a common reason for the check engine light to come on. The light may be steady or flashing. A flashing light indicates a serious misfire that requires immediate attention. 🎬 Watch: Diagnosing engine misfires and rough running issues
- Rough Engine Idle: Your Pilot may shake or vibrate more than usual when you are stopped at a light.
- Poor Acceleration: The engine may feel sluggish or hesitant when you press the gas pedal.
- Reduced Fuel Economy: If your engine isn't burning fuel efficiently, you'll find yourself visiting the gas station more often.
- Trouble Starting: Worn plugs can make it difficult for the engine to start, especially in cold weather.
Choosing the Right Aftermarket Spark Plugs
For the 3.5L V6 engine in the 2004-2008 Pilot, sticking close to the original equipment (OEM) design is the best choice. Honda used two main suppliers from the factory: NGK and Denso. You might even find NGK plugs on one side of your engine and Denso on the other from the factory. Both are considered top-tier choices.
Spark Plug Brand Tiers for 2004-2008 Honda Pilot
| Tier | Brands | Quality & Performance Notes |
|---|---|---|
| OEM / Premium Aftermarket | NGK, Denso | These are the original equipment brands and are highly recommended. Look for their Iridium or Platinum long-life plugs (like NGK IZFR5K11 or Denso SKJ16DR-M11) for performance and longevity that matches the factory parts. |
| Mid-Grade Aftermarket | Autolite, Bosch | These brands offer iridium and platinum plugs that can be a cost-effective alternative. However, most Honda specialists and owners strongly recommend sticking with NGK or Denso to avoid potential performance issues. |
| Economy | Standard copper plugs from various brands | Copper plugs are cheaper but have a much shorter lifespan (typically 30,000 miles vs. 100,000+ for iridium). They are not recommended for the Pilot's engine, which was designed for long-life plugs. Using them will require much more frequent changes. |
A Note on Spark Plug Fouling and VCM
Some 2006-2008 Honda Pilots are equipped with Variable Cylinder Management (VCM), which deactivates some cylinders to save fuel. This system can sometimes cause oil to get past the piston rings, leading to fouled spark plugs, especially in the rear cylinders. This issue was common enough that Honda issued a Technical Service Bulletin (TSB 13-082) and a warranty extension for later models with similar engines. If you have recurring misfires on the same cylinders even after changing the plugs, it could be a sign of this underlying issue, not just a bad spark plug.
🎬 See how to fix recurring VCM-related misfire problemsEstimated Replacement Costs
The cost to replace spark plugs can vary based on your location and whether you do it yourself or use a professional mechanic. The rear spark plugs on the Pilot's V6 are difficult to access, which increases labor costs at a shop.
🎬 Watch: Step-by-step guide to replacing your own spark plugs| Item | Estimated Cost |
|---|---|
| New Aftermarket Plugs (Set of 6, Premium Iridium) | $60 - $120 |
| Shop Labor | $150 - $350 |
| Total Professional Replacement | $210 - $470 |
Frequently Asked Questions
How often should I change the spark plugs on my 2004-2008 Pilot?
The original iridium spark plugs are designed to last for about 100,000-105,000 miles. Your vehicle's Maintenance Minder system will show a code when it's time for a change. If you are unsure of the vehicle's service history, it's a good idea to replace them if you are near or over 100,000 miles.
Do I need to 'gap' my new spark plugs?
Premium iridium and platinum plugs from NGK and Denso typically come pre-gapped from the factory to the correct specification (0.044 inches). It is wise to check the gap with a feeler gauge, but you must be extremely careful not to touch or damage the fine, brittle center electrode. Never use a coin-style gapper on iridium plugs. If the gap is incorrect, it's often better to get a new plug.
Can I replace just one bad spark plug?
It is strongly recommended to replace all six spark plugs at the same time. Plugs wear down at a similar rate, so if one has failed, the others are likely not far behind. Replacing them all at once ensures balanced engine performance and saves you from having to do the job again in the near future.
Should I use anti-seize on the plug threads?
This is a topic of debate. NGK states that their plugs have a special metal plating that prevents seizing and that adding anti-seize is unnecessary and can cause you to over-torque the plug. However, some mechanics and even the Honda service manual reportedly suggest using a very small amount to prevent the plugs from getting stuck in the aluminum cylinder heads over their long service life. If you do use it, apply only a tiny amount to the threads, avoiding the electrode, and be careful not to overtighten.
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Technical Specifications
OEM Part Numbers: 9807B-5517W 12290-R70-A01 9807B-5515W
Engine requires six spark plugs. The recommended type is Iridium or Platinum with a gap of 0.044 inches. Torque specification for the spark plugs is 13 ft-lbs.
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.
- Honda Passport: