2023 Ram 2500 Spark Plug Type & Gap

Quick reference

Why the right plug matters

Choosing the correct spark plug for your 2023 Ram 2500, especially with the 6.4L Hemi V8, isn't just about getting an engine to run; it's about optimizing performance, fuel efficiency, and longevity. The spark plug is a critical component in the ignition system, responsible for igniting the air-fuel mixture in the combustion chamber.

Heat Range

Spark plugs are designed with a specific "heat range," which refers to their ability to dissipate heat from the combustion chamber. A plug that's too hot (meaning it dissipates heat slowly) can lead to pre-ignition and detonation, causing severe engine damage. Conversely, a plug that's too cold (dissipates heat too quickly) can foul with carbon deposits, leading to misfires and poor performance. The OEM-specified plug is engineered with the precise heat range for your 6.4L Hemi, ensuring optimal combustion temperatures.

Electrode Metal (Iridium vs. Platinum vs. Copper)

The 2023 Ram 2500 6.4L Hemi typically uses a copper-core spark plug with a nickel alloy tip. While not as long-lasting as iridium or platinum, copper is an excellent conductor of electricity, making it ideal for engines with shorter replacement intervals.

• Copper: Excellent conductivity, economical, but wears faster. Usually found in engines with 30,000-mile (48,000 km) service intervals.
• Platinum: Better wear characteristics than copper, good conductivity. Often used in engines with 60,000-mile (96,000 km) or longer intervals.
• Iridium: The hardest and most durable electrode material, offering superior longevity and performance. Typically found in engines with 100,000-mile (160,000 km) or longer intervals.

Using an iridium or platinum plug when not specified can sometimes lead to issues if the heat range or design differs from the OEM copper plug. For the 6.4L Hemi, stick with the specified copper-core plugs.

How to gap a spark plug

Though many modern spark plugs come pre-gapped, it's always a good practice to verify the gap before installation. The 6.4L Hemi requires a precise gap of 0.035 inches (0.9 mm).

1. Obtain a gapping tool: A wire-type spark plug gapping tool is generally preferred over a ramp-style tool, especially for fine-wire electrodes, as it's less likely to damage the tip.
2. Check the gap: Slide the correct wire gauge from your tool between the center and ground electrodes. It should slide in with a slight drag.
3. Adjust if necessary:
   • To increase the gap: Gently pry the ground electrode away from the center electrode using the gapping tool's adjustment slot.
   • To decrease the gap: Carefully tap the ground electrode on a clean, hard surface until the desired gap is achieved.

Be extremely careful not to put pressure on the center electrode or the porcelain insulator, as this can cause damage.

Replacement procedure tips

Replacing spark plugs on your 2023 Ram 2500 6.4L Hemi V8 can be a straightforward DIY task with the right tools and precautions. The 6.4L Hemi uses a coil-on-plug (COP) ignition system, meaning each spark plug has its own ignition coil directly above it.

1. Access: The coils are individually bolted to the valve covers and plug directly into the spark plugs. You'll need to carefully disconnect the electrical connector from each coil, unbolt it, and then pull it straight up to remove it from the spark plug well.
2. Anti-Seize Debate: There's ongoing debate regarding the use of anti-seize on spark plug threads. Mopar (and Champion) typically uses a special coating on their spark plug threads to prevent seizing and provide consistent torque readings. Using additional anti-seize can interfere with this coating and potentially lead to over-torquing the plug, damaging the cylinder head threads. It is generally recommended by modern OEM manufacturers to NOT use anti-seize on coated spark plug threads. Refer to your service manual for the definitive recommendation.
3. Dielectric Grease: A small amount of dielectric grease applied inside the spark plug boot (the end that connects to the spark plug) can aid in future removal and provide a better seal, protecting against moisture and corrosion. Do not apply dielectric grease to the electrical connector pins.
4. Torque Specification: Adhere strictly to the torque specification of 13 lb-ft (18 Nm). Over-tightening can damage the spark plug and the cylinder head threads, while under-tightening can lead to combustion gas leaks and spark plug overheating.
5. One at a Time: Replace plugs one at a time to avoid dropping debris into open cylinders and to ensure the correct coil pack goes back onto its corresponding plug.

Known issues

Fortunately, the 6.4L Hemi V8 in the 2023 Ram 2500 isn't known for any widespread, specific spark plug-related issues like the notorious two-piece spark plug breakage seen on older Ford 3-valve engines. However, general considerations apply:

• Misfires: The most common sign of a failing spark plug is an engine misfire, which can cause rough idling, reduced power, and a check engine light. This often presents as a sputtering or hesitation during acceleration.
• Coil Pack Failure: While not a spark plug issue itself, a failing coil pack can mimic spark plug symptoms. If you have a misfire, it's wise to inspect both the spark plug and its corresponding coil pack.
• Fouling: Excessive oil consumption or rich fuel conditions can lead to spark plug fouling (deposits on the electrodes), causing misfires. This usually indicates an underlying engine issue that needs addressing.

Need plugs replaced? Find a shop on Repairius.