2020 Tesla Model 3 Spark Plug Type & Gap

Quick reference

Why the right plug matters

For most gasoline-powered vehicles, selecting the correct spark plug is crucial for optimal engine performance, fuel efficiency, and emissions. Factors like heat range, electrode material, and gap directly impact how the spark plug functions within the combustion chamber. Spark plugs come in various types, including copper, platinum, and iridium.

• Heat Range: A spark plug's heat range refers to its ability to dissipate heat. A plug that's too hot can lead to pre-ignition and detonation, damaging the engine. A plug that's too cold can cause fouling as carbon deposits build up.
• Electrode Material:
  • Copper: Copper plugs have a large-diameter copper core and are excellent conductors. They are typically the cheapest option but have the shortest lifespan.
  • Platinum: Platinum plugs use a platinum disc welded to the center electrode. Platinum is harder and more durable than copper, leading to a longer lifespan and more consistent performance.
  • Iridium: Iridium is even harder and more corrosion-resistant than platinum, allowing for smaller-diameter electrodes. This results in a more concentrated spark, improved ignition efficiency, and the longest lifespan.

How to gap a spark plug

While some spark plugs are "pre-gapped" from the factory, it's always a good idea to double-check and adjust the gap if necessary, especially for gasoline engines. The gap is the distance between the center and ground electrodes. An incorrect gap can lead to misfires, reduced power, and poor fuel economy.

To gap a spark plug, you'll typically use a wire-style or coin-style spark plug gap tool. Carefully insert the tool between the electrodes and gently bend the ground electrode to achieve the specified gap. Be very careful not to damage the delicate center electrode, especially on iridium or platinum plugs.

Replacement procedure tips

When replacing spark plugs in a gasoline engine, there are several general tips that apply:

• Coil-on-plug removal: Most modern vehicles use coil-on-plug ignition systems, where an individual ignition coil sits directly on top of each spark plug. Carefully disconnect the electrical connector and remove the coil by pulling it straight up.
• Anti-seize debate: There's ongoing debate about whether to use anti-seize compound on spark plug threads. Some manufacturers advise against it, while others recommend a small amount. If used, apply sparingly to the threads, avoiding contact with the electrode or insulator.
• Dielectric grease on boots: Applying a small amount of dielectric grease inside the spark plug boot (the rubber part that connects the coil or wire to the plug) can help prevent moisture intrusion and make future removals easier.

Known issues

For a gasoline-powered vehicle, some common spark plug-related issues can include:

• Cracked porcelain: Over-tightening or dropping a spark plug can crack the porcelain insulator, leading to misfires.
• Broken plug shells: In some Ford 3-valve engines, a notorious two-piece spark plug design was prone to seizing in the cylinder head and breaking during removal.

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