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Spark Plugs: Iridium Spark Plug | ACDelco

ACDelco Professional Iridium Spark Plugs are the ideal high-quality replacement for many vehicles on the road today. They are the latest in spark plug technology and an exact replacement for your vehicle’s original components. Iridium composition has the highest melting point and strength of all metals. It provides the greatest wear resistance and durability over Platinum and Conventional spark plugs. ACDelco Professional Iridium Spark Plugs provide the best wear resistance and durability of any spark plug. These premium aftermarket replacement iridium spark plugs are manufactured to meet and exceed your expectations for fit, form and function.


  • Iridium offers better engine idle stability and smoother performance
  • Iridium allows for smaller, more efficient electrode designs for improved cold starting and quicker acceleration
  • Iridium fine-wire electrode helps improve ignition of the fuel and burns away carbon deposits on the tip of the plug as they form, to help improve fuel economy
  • One-piece suppressor seal blocks radio frequencies that can affect vehicle electronics
  • Suppressor seal meters spark energy for longer electrode life and seals against combustion leakage


Find out more about the ACDelco Professional Iridium Spark Plug and how it fits into the Starting and Charging System with the product facts below.


Uses a high-voltage spark from the ignition coil to ignite the air/fuel mixture inside the engine’s cylinders.

Signs of Wear & Troubleshooting:

  • Engine has trouble starting, hesitates, or cuts out.
  • Sluggish engine performance, loss of engine power, or decreased fuel economy.
  • Lack of acceleration or loss of speed when driving uphill.
  • Cracks in the upper or lower portion of the spark plug insulator.
  • Chipped or broken insulator tip.
  • Damaged spark plug boot.


What It Does:

The Starting and Charging System starts the engine, maintains the battery’s charge and provides power to the electrical accessories while the engine is running.

Good Maintenance Practices:

It is important to inspect spark plugs at regular intervals for signs of deterioration. Follow these steps for removing spark plugs for inspection, servicing or replacement:

  • Grasp the spark plug boot and gently rotate it 90 degrees counterclockwise. Pull the spark plug boot and cable away from the spark plug. If necessary, use spark plug boot removing tool. DO NOT grab or violently pull spark plug cables.
  • Use the correct deep socket size to loosen each spark plug one or two turns. NOTE: To remove spark plugs from aluminum heads, allow the engine to cool. The heat of the engine, in combination with a spark plug that is still hot, may cause the spark plug threads to strip the cylinder head upon removal.
  • Brush or air-blast dirt away from the well areas before removing spark plugs. CAUTION: Use goggles to protect eyes from dirt when applying compressed air to spark plug wells.
  • Remove each spark plug and place each one in a tray by cylinder number. This will help identify and relate any unusual condition to the cylinder involved.
  • Apply dielectric grease into the boot area to reduce the chance of exterior tracking on the buttress tower of the spark plug. This grease also promotes a good heat transfer between the spark terminal screw and boot terminal.
  • Before installing new spark plugs, use a gap guide to make sure your new spark plugs have the correct gap. NOTE: ACDelco Professional Iridium Spark Plugs are pre-gapped during manufacturing. Never attempt to gap an ACDelco Professional Iridium Spark Plug. You could damage the spark plug. Replace the incorrectly gapped ACDelco Professional Iridium Spark Plug with one that is correctly gapped.


  • FAQs:

    Should I change my spark plugs every 3,000 miles?

    • No, it depends on what type of spark plug your vehicle requires. Refer to your Owner’s Manual or contact your vehicle’s manufacturer for more information.

    Can changing my spark plugs improve my engine’s performance?

    • Yes, but spark plugs may not be the only factor impacting performance. Replacing old spark plugs may temporarily improve poor engine performance due to reduced demand on the ignition system. However, this is not the cure for poor engine performance caused by worn rings, faulty carburetion, worn distributor parts or other engine performance issues.

    Should I change all of my vehicle’s spark plugs at the same time?

    • Yes, if it is the scheduled time for spark plug replacement. It may be OK to replace one spark plug if it was broken for any reason prior to scheduled maintenance.

    Does a diesel engine require a different type of plug than a gas engine?

    • Yes. Diesel engines require glow plugs because diesel engine ignitions operate differently than gas engines. ACDelco Professional Glow Plugs are specially designed to give diesel engines the heat they need for their cold starts.

    Are ACDelco spark plugs pre-gapped?

    • Yes. When ACDelco spark plugs are manufactured, they are pre-gapped to the correct gap specification.

    When I replace my spark plugs, should I also replace my spark plug wires?

    • Not always. Refer to your vehicle Owner’s Manual or contact the manufacturer for more information.

    How do spark plugs become fouled?

    • Certain engine conditions can cause oil, powder and carbon to collect on the spark plug, causing a misfire. See our list of Signs and Causes of Spark Plug Wear.

    What is pre-ignition and can it damage my engine?

    • Yes, pre-ignition can cause serious damage to your engine. Pre-ignition happens when the spark plug is too hot and fires before the piston is in the correct position.

    Can I just clean my spark plugs instead of replacing them?

    • No, cleaning your old spark plugs is not recommended. Dirty, fouled spark plugs may also have broken, chipped insulator tips, worn electrodes or worn or missing side wires. These conditions severely affect spark plug performance. Replace your dirty, fouled spark plugs with new ACDelco spark plugs.

    Does ACDelco have marine spark plugs?

    • Yes, ACDelco has marine spark plugs for many applications.

    • Limited Warranty:

      100,000 Miles/Unlimited Months*

*To the original retail purchaser. Parts only; installation not included. See your local retailer or Independent Service Center that offers ACDelco Parts for details.

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