Yes, you should always check the gap on iridium spark plugs, even though they come pre-gapped; the fine iridium tip is delicate, so you must use extreme caution, a feeler gauge, and avoid wedging tools, gently adjusting only the ground strap with pliers or tapping it lightly to prevent breakage, as proper gapping ensures optimal performance and longevity.
You do NOT need to gap an iridium plug. It's not recommended as it wears off the very thin plating on the electrode.
Commonly, newer spark plugs designed with precious metals like iridium, platinum, or ruthenium should be gapped with a feeler or wire-type gap gauge. However, a coin-style gap tool can be used if your vehicle uses copper/nickel spark plugs.
Though pre-gapped spark plugs are convenient, they might need to be more suited for your specific engine type. Always measure the gap to guarantee optimal performance and durability of your vehicle's spark plug. Even with pre-gapped spark plugs, it's wise to double-check.
While plugs are pre-gapped from the factory, the gap may need to be adjusted for the vehicle that the spark plug is intended for. Those with modified engines must remember that higher compression or forced induction will typically require a smaller gap setting (to ensure ignitability under higher pressure).
Overheating: Overheating can cause the spark plug's electrodes to wear out more quickly. This is often due to issues like incorrect spark plug gap, poor fuel quality, too little fuel available for combustion, or engine overheating.
Feeler Gauge
Ideal for use with iridium spark plugs and other plugs containing precious metals, feeler gauges are more accurate than other types. A drawback is the fact that you'll need a pair of pliers to bend the spark plug electrode since the blades will become deformed if you try using them to adjust the plug.
The main disadvantages of iridium spark plugs are their significantly higher cost and increased fragility, requiring careful handling during installation, as the fine iridium tip can be easily damaged, negating benefits and potentially causing engine issues; they also can't be cleaned if fouled, meaning a fouled plug must be replaced, unlike some copper plugs.
Don't gap an iridium or platinum plug, side gap or otherwise, attempting to do so would compromise the iridium/platinum on the plug, as far as copper plugs, I have no idea if it (side gapping) would make an appreciable difference.
The estimated mileage of iridium spark plugs – depending on the thickness of the central electrode and the construction of the ground electrode – ranges from 60,000 km up to 120,000 km in the case of DENSO Super Ignition Spark Plugs, which feature a protruding ground electrode, like DENSO's Twin Tip (TT) Spark Plugs.
Always use a special spark plug gapping tool to change the gap. Do not change the gap on platinum, iridium or twin tip spark plugs, as the fine electrodes may get damaged.
Cons of Iridium Spark Plugs
The best models use two or three layers of iridium on the central electrode, whereas the cheapest models may use only one thin layer. These can be prone to cracks and impact damage, so for the best results, always invest in a double or triple coated spark plug.
they should come pregapped, but yes, check them if they look odd with a wire gap tester. then, if it does need adjustment, a small pair of needle nose pliers or one of the hook electrode adjusting tools is needed.
Spark plugs that do not have the proper gap lead to premature wear, ignition system stress, and even cylinder misfires.
Symptoms can include a misfire code in the ECM, stumbling and stalling, rough running, and poor fuel efficiency, and a visual inspection can reveal the spark plugs are worn or contaminated.
Iridium spark plugs have a fine wire center electrode that requires less voltage to create a spark. This results in a more efficient combustion process, better fuel economy, and a smoother idle.
Do iridium spark plugs increase horsepower? Not directly, but they improve combustion efficiency, leading to smoother acceleration.
If your owner's manual specifies iridium spark plugs, don't downgrade to platinum spark plugs or copper spark plugs; if you downgrade, you run the risk of poor engine performance. You can also consult your mechanic for guidance on selecting the best spark plug for your car.
Generally, both brands offer impressive life, but NGK's iridium plugs tend to slightly outlast their Denso counterparts, particularly under harsh driving conditions.
If you can't get the correct feeler gauge through the gap, the gap needs to be widened. If the tool runs through the gap without touching the electrodes, the gap is too big and must be narrowed. Use your spark plug gap tool to adjust the gap.
WD-40 Multi-use Product is ideal for cleaning spark plugs. Spray WD-40 Multi-use Product on a microfiber cloth and rub over the spark plug. You can even spray WD-40 directly on the spark plug & then wipe it down using a soft, clean cloth.
Because your vehicle's engine is not operating at its peak temperature when idling, fuel is only partially combusted, leading to a fuel residue buildup on cylinder walls. This is the gunk that can foul your sparkplugs and muck up your exhaust systems.
Diagnosing Head Gasket Leak Signs from Spark Plug Condition
If spark plugs don't appear steam cleaned, it doesn't rule out a head gasket leak. A blown head gasket can cause coolant to enter the combustion chamber, leaving deposits or steam-cleaned plugs. Inspect for symptoms like white smoke, overheating, or milky oil.