2015 Honda Odyssey Spark Plug Type & Gap

Quick reference

Why the right plug matters

Spark plugs are vital for your engine's performance, fuel economy, and emissions. Choosing the correct plug for your 2015 Honda Odyssey's 3.5L V6 engine is crucial. Modern engines, like yours, are designed to work optimally with specific spark plug characteristics, including heat range, electrode material, and gap.

• Heat Range: This refers to the plug's ability to dissipate heat from the combustion chamber. A plug that's too "cold" won't burn off carbon deposits effectively, leading to fouling. A plug that's too "hot" can overheat, causing pre-ignition and engine damage. The NGK DILZKR7A11GS is engineered with the precise heat range for your Odyssey.
• Electrode Metal: The 2015 Honda Odyssey typically uses long-life iridium plugs from the factory. Iridium is a precious metal with an extremely high melting point and exceptional hardness, allowing for very fine electrodes that provide a strong, consistent spark for much longer than traditional copper or even platinum plugs. This translates to extended replacement intervals, greater fuel efficiency, and smoother operation. While copper plugs offer excellent conductivity and a powerful spark, their wear rate is significantly higher, leading to much shorter service intervals. Platinum plugs offer a lifespan between copper and iridium.

How to gap a spark plug

While most modern iridium spark plugs come pre-gapped from the factory, it's always a good idea to double-check the gap before installation, especially with high-performance or sensitive engines. However, it's critical to be extremely careful with iridium plugs. The fine iridium tip can be easily damaged if you use a traditional coin-style gap tool.

For iridium plugs, use a wire-style or feeler gauge. If adjustment is necessary, gently bend the ground electrode only. Never pry against the delicate center electrode or the iridium tip, as this will almost certainly damage the plug and lead to misfires.

For your 2015 Honda Odyssey, the recommended gap is 0.044 inches (1.1 mm).

Replacement procedure tips

Replacing spark plugs on your 2015 Honda Odyssey's 3.5L V6 engine involves a few key steps and considerations:

1. Safety First: Always ensure the engine is cool and disconnect the negative battery terminal before starting any work.
2. Access: The 3.5L V6 in the Odyssey often has the rear bank of cylinders (cylinders 1, 3, 5) located under the intake manifold, which can make them challenging to access. This may require removing or at least loosening parts of the intake system to gain proper access to the coil-on-plug units.
3. Coil-on-Plug Removal: Your Odyssey uses a coil-on-plug ignition system. Each spark plug has its own ignition coil directly mounted on top. Carefully disconnect the electrical connector from each coil and then remove the coil hold-down bolt (if present). Gently twist and pull the coil straight up to remove it. Avoid prying, which can damage the coil or the spark plug tube seal.
4. Cleaning: Before removing the old spark plugs, use compressed air to blow any debris out of the spark plug wells. This prevents dirt and grime from falling into the combustion chamber once the old plug is removed.
5. Anti-Seize Debate: There's ongoing debate about using anti-seize on spark plug threads. For spark plugs with nickel-plated shells, like many modern NGK and Denso plugs, anti-seize is generally not recommended by the manufacturer. The nickel plating provides adequate corrosion protection and prevents seizing. Applying anti-seize can also alter the torque readings, potentially leading to over-tightening and plug damage. Follow the spark plug manufacturer's recommendations. If you choose to use it, use a very small amount on the threads, avoiding the electrode, and reduce the torque specification by about 10-20%.
6. Dielectric Grease: Apply a thin layer of dielectric grease to the inside of the spark plug boot (the part that connects to the top of the spark plug, within the coil). This helps to seal out moisture, prevents corrosion, and makes future removal easier. Be careful not to get any grease on the electrode tips of the spark plug.
7. Torque Specification: Tighten the new spark plugs to the manufacturer's recommended torque specification, which is 13 lb-ft (18 Nm) for your Odyssey. Using a torque wrench is crucial to prevent over-tightening (which can damage the threads in the cylinder head or crack the plug) or under-tightening (which can lead to misfires or the plug backing out).

Known issues

While the 2015 Honda Odyssey's 3.5L V6 engine is generally reliable, there are no widespread, specific spark plug-related "known issues" like the infamous two-piece spark plug breakage in some Ford 3-valve engines. Sticking to the OEM recommended iridium plugs and following proper replacement procedures will ensure a long and trouble-free service life.

Need plugs replaced? Find a shop on Repairius.