ACDelco stands for quality. Get the performance you need with ACDelco products. 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 products are developed to exceed your performance expectations and deliver the durability you expect.


• 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


Signs that your spark plugs need to be replaced include but are not limited to:
• 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 under load.
• Cracks in the upper or lower portion of the spark plug insulator.
• Chipped or broken insulator tip.
• Damaged spark plug boot.


Visually inspect spark plugs for signs of wear. 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 Iridium Spark Plugs are pre-gapped during manufacturing. Never attempt to gap an ACDelco Iridium Spark Plug. You could damage the spark plug. Replace the incorrectly gapped ACDelco Iridium Spark Plug with one that is correctly gapped.
• Install spark plugs or glow plugs to the proper torque per the manufacturers’ specification.


Q: Should I change my spark plugs every 30,000 kilometers?
A: 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.

Q: Can changing my spark plugs improve my engine’s performance?
A: Yes. However, 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 mechanical components, improper fuel delivery, worn ignition parts, or other engine performance issues.

Q: Should I change all of my vehicle’s spark plugs at the same time?
A: Yes. All of the spark plugs should be changed if it is the scheduled time for spark plug replacement. However, it is okay to replace one spark plug if it is fouled or damaged prior to scheduled maintenance, provided the source of the damage is found and corrected.

Q: Are ACDelco spark plugs pre-gapped?
A: Yes. When ACDelco spark plugs are developed, they are pre-gapped to the correct gap specification.

Q: When I replace my spark plugs, should I also replace my spark plug wires?
A: Not always, but you should inspect your spark plug wires for wear when replacing your spark plugs. Refer to your vehicle owner’s manual or contact the manufacturer for more information.

Q: How do spark plugs become fouled?
A: Certain engine conditions can cause oil, powder, and carbon to collect on the spark plug causing a misfire.

Q: What is pre-ignition and can it damage my engine?
A: Yes. Pre-ignition can cause serious damage to your engine. Pre-ignition is the ignition of fuel before the actual spark occurs, which causes a rapid temperature rise in the combustion chamber that can damage engine components and melt spark plug electrodes. Causes of pre-ignition include but are not limited to a buildup of deposits that can become incandescent in the combustion chamber, improper installation torque being applied to spark plugs, and having spark plugs with a heat range that is too hot for the engine’s operating condition.

Q: Can I just clean my spark plugs instead of replacing them?
A: 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.