A Home Mechanic's Guide to 2011-2013 INFINITI M37 Spark Plugs
Keep your M37's powerful V6 engine running smoothly by choosing the right spark plugs for the job.
- Stick with OEM-equivalent Iridium spark plugs from Denso or NGK for best performance and reliability.
- The factory recommended replacement interval is 105,000 miles, but symptoms can appear sooner.
- Always verify the spark plug gap is 0.044 inches before installation, even on pre-gapped plugs.
- Replacement is a feasible DIY job but requires removing the throttle bodies to access all six plugs.
Signs Your M37 Needs New Spark Plugs
The original spark plugs in your M37 are designed to last a long time, with a recommended service interval of around 105,000 miles. However, they can wear out sooner. When they start to fail, you'll notice clear signs that your car isn't running right. Ignoring these symptoms can lead to poor performance, bad fuel economy, and potentially expensive damage to your catalytic converters.
- Rough Idle: The engine may shake or vibrate more than usual when you're stopped.
- Engine Misfires: You might feel a hesitation or stumble during acceleration. This is often accompanied by a flashing check engine light.
- Poor Acceleration: The car may feel sluggish and less responsive than it used to be.
- Reduced Fuel Economy: If you're filling up your gas tank more often, worn spark plugs could be the cause.
- Check Engine Light: A failing spark plug is a common reason for the check engine light to come on, often with codes like P0300 (random misfire) or P0301-P0306 (misfire on a specific cylinder). 🎬 Watch: Diagnosing a P0301 cylinder misfire on an M37
Choosing the Right Aftermarket Spark Plugs
When shopping for spark plugs for your M37, you'll see options from brands like NGK, Denso, Bosch, and Champion. For this specific vehicle, the choice matters. The original factory spark plugs are typically made by Denso. Both Denso and NGK are considered top-tier OEM (Original Equipment Manufacturer) suppliers for Japanese vehicles and are highly recommended by INFINITI owners and mechanics.
Aftermarket Brand Tiers for INFINITI M37
| Tier | Brands | Quality & Performance Notes |
|---|---|---|
| Tier 1 (OEM-Equivalent) | Denso, NGK | These brands are the original equipment suppliers. They provide the most reliable performance and longevity. Choosing their Iridium plugs, like the Denso FXE24HR11 or NGK Laser Iridium equivalents, is the safest bet for your engine. |
| Tier 2 (Reputable Aftermarket) | Bosch | Bosch makes quality Iridium spark plugs that are a viable alternative. While not the OEM brand, they are a well-respected manufacturer and generally perform well in many vehicles. |
| Tier 3 (Economy) | Champion, Autolite | While these brands offer iridium plugs at a lower price point, owner and forum feedback strongly favors sticking with Denso or NGK for the VQ37VHR engine to avoid potential performance issues. They are a budget-friendly option but may not offer the same longevity or precise performance as the OEM brands. |
Pro Tip: Always use Iridium spark plugs in your M37. The engine was designed for them. Cheaper platinum or copper plugs will not perform as well and will wear out much faster, costing you more in the long run.
🎬 Watch: Why you shouldn't delay your spark plug replacementKnown Issues, Recalls, and Service Bulletins
As of early 2026, there are no specific recalls or Technical Service Bulletins (TSBs) from INFINITI or the NHTSA directly related to spark plugs for the 2011-2013 M37. However, there was a recall for some 2011-2012 models concerning a fuel pressure sensor that could loosen and cause a fuel leak, which can sometimes be misdiagnosed if not properly inspected. There are no widespread, documented problems with the original spark plugs themselves.
Frequently Asked Questions (FAQ)
How often should I change the spark plugs on my M37?
The manufacturer's recommended service interval is typically 105,000 miles for the original iridium spark plugs. However, if you experience any symptoms of failure, you should inspect them sooner.
What is the correct spark plug gap for the M37?
The recommended spark plug gap is 0.044 inches (1.1mm). While most high-quality iridium plugs come pre-gapped, it is crucial to verify the gap on each plug with a feeler gauge before installation. Do not use a coin-style gapper, as it can damage the fine iridium tip.
Should I replace all six spark plugs at once?
Yes. Spark plugs should always be replaced as a full set of six. This ensures even wear and consistent performance across all engine cylinders. Replacing only one can cause an imbalance in engine operation.
Is it difficult to change the spark plugs myself?
The job is moderately difficult for a DIY mechanic. While the front plugs on each side are easy to access, reaching the rear plugs requires removing the engine cover and both throttle bodies. If you are not comfortable with this, it's best to have a professional do the work.
🎬 See this step-by-step spark plug and ignition coil walkthroughDo I need to use anti-seize on the new spark plug threads?
Most modern NGK and Denso plugs have a special trivalent plating that acts as an anti-seize. The manufacturers advise against using additional anti-seize compound, as it can lead to over-torquing and potential damage to the plug or cylinder head. Always follow the plug manufacturer's specific instructions.
Helpful Videos
Technical Specifications
OEM Part Numbers: 22401-JK01D
Material: Iridium, Recommended Gap: 0.044" (1.1mm), Quantity Required: 6
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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.
- INFINITI M37: