The Infiniti G37, a popular luxury sports sedan and coupe, uses a 3.7-liter V6 engine. Understanding its spark plug count, replacement intervals, and maintenance needs helps owners keep the vehicle running smoothly. This article explains how many spark plugs the G37 has, why that matters, and practical steps for inspection and replacement.
Spark Plug Count For The Infiniti G37
The Infiniti G37 is equipped with a 3.7-liter V6 engine that uses one spark plug per cylinder. With six cylinders in total, the G37 has **six spark plugs**. This configuration is standard for many modern V6 engines and supports reliable ignition, efficient combustion, and smooth performance across RPM ranges.
Why The Spark Plugs Matter
Spark plugs create the ignition spark that starts the air-and-fuel mixture in each cylinder. Worn or fouled plugs can cause misfires, reduced fuel economy, rough idle, and power loss. For a performance-oriented car like the G37, optimal spark timing and stable combustion contribute to responsive acceleration and consistent handling.
Replacement Interval And Maintenance
Manufacturers provide recommended replacement intervals that can vary by model year, driving conditions, and spark plug type. Common guidance for many V6 engines in similar vehicles is to replace plugs every 60,000 to 100,000 miles when using iridium or platinum plugs. If using copper plugs, expect a shorter interval, typically around 30,000 to 40,000 miles. Always refer to the owner’s manual for the exact interval for the G37’s engine code and spark plug type.
Factors that may shorten the interval include:
- Severe driving conditions (short trips, frequent idling, towing, or high-load trips)
- Poor fuel quality or oil leaks reaching the combustion chamber
- High-performance variants or aftermarket ignition components
- Incorrect gap set during installation
Symptoms Of Worn Or Faulty Spark Plugs
Recognizing wear early can prevent more serious engine problems. Common symptoms include:
- Rough idle or misfires at idle
- Unstable engine performance or hesitation during acceleration
- Decreased fuel economy and reduced power
- Engine warning light or misfire codes (P0300-series)
- Difficulty starting or longer cranking times
If symptoms persist, have the ignition system checked, and consider compression tests to rule out other issues such as coil packs or fuel delivery problems.
Choosing The Right Spark Plugs For The G37
Choosing the correct spark plug type is essential for reliability and performance. For the G37, options typically include:
- Platinum or iridium center electrodes for longevity and stable performance
- Copper plugs for lower cost but shorter life
- OEM-recommended heat range to prevent pre-ignition or fouling
When selecting plugs, verify:
- Exact part number compatible with the vehicle’s engine code
- Proper heat range to match the G37’s air-fuel mixture and compression
- Correct thread size and gasket type to avoid cross-threading or leaks
Tools And Safety For Spark Plug Replacement
Before starting, gather essential tools and follow safety precautions:
- Socket wrench with deep 6-point socket, spark plug socket, and extension
- Torque wrench for precise tightening
- New spark plugs and anti-seize or dielectric grease as recommended
- Compressed air to clear debris from spark plug wells
- Gloves, eye protection, and a clean workspace
Safety note: disconnect the negative battery cable before beginning work, and allow the engine to cool to avoid burns.
Step-By-Step Replacement Process
The process is generally straightforward but may vary slightly by model year or engine variant. Follow these steps carefully:
- Disconnect the negative battery terminal to prevent electrical shock.
- Remove engine cover if present and locate the six ignition coils over each cylinder.
- Use compressed air to clean spark plug wells, preventing debris from falling into the combustion chamber.
- Unplug each coil or ignition wire, then remove the coil to access the spark plug.
- Use a spark plug socket with extension to carefully loosen and remove the old plug. Do not apply brute force.
- Inspect the threads in the cylinder head; if damaged, address before installation.
- Set the gap on new plugs as specified in the owner’s manual or by the plug manufacturer.
- Thread the new plug by hand to avoid cross-threading, then snug with a torque wrench to the manufacturer’s specification.
- Reinstall coils, reconnect electrical connections, and replace the engine cover.
- Reconnect the battery and start the engine to confirm proper operation and absence of misfires.
Post-Replacement Maintenance And Tips
After replacing spark plugs, consider the following to maximize performance and longevity:
- Reset the vehicle’s ECU if recommended by the manufacturer; some cars automatically relearn after driving.
- Replace ignition coils in pairs if they show wear signs to prevent imbalanced performance.
- Use high-quality fuel and avoid new mix ratios until the engine completes a few drive cycles.
- Keep air filters clean to ensure consistent air intake and combustion efficiency.
- Schedule regular inspections to monitor ignition system performance during service intervals.
Frequently Asked Questions
Common questions about the Infiniti G37 spark plugs include:
- How many spark plugs does a G37 have? Six, one per cylinder on the V6 engine.
- What is the recommended replacement interval? It depends on spark plug type; commonly 60,000–100,000 miles for iridium/platinum, shorter for copper plugs.
- Can I replace spark plugs myself? Yes, with proper tools and caution, though some models may have tight access; consult the manual for specifics.
- What are signs of worn plugs? Rough idle, misfires, reduced power, poor gas mileage, and hard starting.
