2017 Ram 3500 Spark Plug Type & Gap

Quick Reference

(Note: Spark plug part numbers and specifications are subject to change. Always verify with your vehicle's owner's manual or a reputable parts catalog.)

Why the right plug matters

Choosing the correct spark plug for your 2017 Ram 3500 is crucial for optimal engine performance, fuel efficiency, and longevity. Using the wrong plug can lead to misfires, reduced power, poor fuel economy, and even costly engine damage. There are a few key factors to consider:

• Heat Range: Spark plugs are designed with a specific "heat range" – how quickly they transfer heat away from the combustion chamber. A plug that's too "hot" (slow heat transfer) can overheat and cause pre-ignition or detonation, while a plug that's too "cold" (fast heat transfer) can foul with carbon deposits. Your Ram's engine is designed for a specific heat range, and using anything different can lead to problems.

• Electrode Metal: The material of the spark plug's electrode significantly impacts its lifespan and performance.

  • Copper: Traditional and excellent at conducting electricity, copper plugs are typically found in older vehicles or those with high-performance demands requiring frequent changes. The 5.7L HEMI often uses copper-nickel alloy plugs, which have a shorter lifespan but are very effective for its design.
  • Platinum: More durable than copper, platinum plugs offer a longer service life, making them a common choice for many modern engines. They resist wear better, maintaining a consistent spark over thousands of miles.
  • Iridium: The hardest and most durable of the three, iridium plugs provide the longest service life and the finest electrode tip, leading to a very focused and efficient spark. The 6.4L HEMI utilizes iridium plugs for their extended durability and consistent performance.

How to gap a spark plug

The spark plug gap is the distance between the center and ground electrodes. This gap is critical for a strong, consistent spark. While many modern spark plugs come "pre-gapped," it's always a good practice to double-check and adjust if necessary, especially for non-iridium plugs. Always refer to the specifications in the quick reference table.

1. Obtain a Gap Tool: Use a wire-type spark plug gap gauge. Avoid disc-style gauges as they can damage the fine electrode tips of iridium or platinum plugs.
2. Measure the Gap: Carefully insert the correct wire gauge between the electrodes. It should slide through with slight drag.
3. Adjust (if needed):
   • To increase the gap: Gently bend the ground electrode outwards using the notching tool on your gap gauge.
   • To decrease the gap: Carefully tap the ground electrode on a clean, hard surface. Be extremely gentle, especially with iridium or platinum plugs, as their tips are fragile. Never push or pry on the center electrode.
4. Re-measure: Re-check the gap until it matches the specification precisely.

Replacement procedure tips

Replacing spark plugs on your 2017 Ram 3500 (both 5.7L and 6.4L HEMI engines) involves similar steps. Both engines utilize a coil-on-plug (COP) ignition system, meaning each spark plug has its own ignition coil directly mounted on top of it.

1. Safety First: Ensure the engine is cool, disconnect the negative battery terminal to prevent accidental starting or electrical shorts.
2. Access: You may need to remove engine covers or air intake components to gain full access to the coil packs.
3. Coil-on-Plug Removal: Carefully disconnect the electrical connector from each coil pack by pressing the release tab. Then, firmly pull upwards on the coil pack to remove it from the spark plug well. They can sometimes be stuck, so gentle wiggling might be necessary.
4. Clean the Area: Before removing the old plugs, use compressed air to blow out any dirt or debris from around the spark plug wells. This prevents contaminants from falling into the combustion chamber when the old plug is removed.
5. Remove Old Plugs: Use a spark plug socket (typically 5/8" or 13/16") with an extension and ratchet. Turn counter-clockwise to remove. Inspect the old plugs for signs of wear, fouling, or other issues.
6. Anti-Seize Debate: There is ongoing debate about using anti-seize on spark plug threads. Modern spark plugs often have a special coating and don't require it, especially if the plug body is nickel-plated. Applying anti-seize can alter torque readings, leading to over-tightening. If you choose to use it (sparingly), reduce the specified torque by about 10-20%. Consult the spark plug manufacturer's recommendations.
7. Install New Plugs: Thread the new plugs in by hand first to avoid cross-threading. Once finger-tight, use your torque wrench to tighten them to the specified torque. Over-tightening can damage the plug or the cylinder head threads, while under-tightening can lead to blow-by and misfires.
8. Dielectric Grease: Apply a small amount of dielectric grease inside the spark plug boot (the rubber end of the coil pack) before reinstalling. This helps prevent moisture entry, reduces voltage leaks, and makes future removal easier.
9. Reinstall Coils and Components: Reconnect the coil pack electrical connectors, reinstall any removed components, and reattach the battery terminal.

Known Issues

Fortunately, the 2017 Ram 3500 with either the 5.7L or 6.4L HEMI engine does not suffer from widespread known issues related specifically to spark plug design, such as the infamous two-piece spark plug breakage issues seen in some Ford 3-valve engines.

However, general issues that can affect spark plug performance in these engines include:

• Oil Fouling: Valve cover gasket leaks or excessive oil consumption can lead to oil fouling on the spark plugs, causing misfires.
• Carbon Buildup: Direct injection engines can be prone to carbon buildup on intake valves, which, while not a direct spark plug issue, can affect combustion and manifest as misfire-like symptoms.
• Coil Pack Failure: While durable, individual ignition coil packs can fail over time, leading to misfires on a specific cylinder. If you experience a misfire, it's important to diagnose whether it's the plug, coil, or another issue.

Need plugs replaced? Find a shop on Repairius.