Tips
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 a spark plug boot removing tool. DO NOT grab or violently pull spark plug cables.
- Brush or air blast dirt away from the well areas before removing spark plugs. CAUTION: Use goggles to protect eyes from debris when applying compressed air to spark plug wells.
- 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.
- 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 any incorrectly gapped ACDelco Professional Iridium Spark Plugs with plugs that are correctly gapped.
- Install spark plugs or glow plugs to the proper torque per the manufacturers' specification.
Troubleshooting
Signs of wear for spark plugs include but are not limited to:
- Your engine having trouble starting, hesitating, or cutting 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 tips
- Damaged spark plug boots