ACDelco GM Original Equipment LS Iridium Spark Plug
Denso Iridium #20 Also used in TA2 engines
Seat Type |
Tapered |
Grade Type |
Performance |
Gap Size |
0.04 in |
Gap Size |
1.02 mm |
Classification |
OE |
Reach |
17.5 mm |
Insulator Height |
2.07 in |
Insulator Height |
52.7 mm |
Manufacturer Heat Range |
20 |
Reach |
0.69 in |
Ground Electrode Quantity |
1 |
Center Electrode Tip Material |
Iridium |
Washer Included |
No |
Resistor Type |
Yes |
Ground Electrode Tip Design |
Standard |
Hex Size |
15.95 MM |
Ground Configuration |
Standard |
Keep your engine running at peak performance with proper spark plug care. Whether you are experiencing engine hesitation, poor acceleration, or difficulty starting, a fresh set of spark plugs can restore your vehicle's power and fuel efficiency.
Follow these professional maintenance practices to ensure a safe and effective installation.
Before beginning, ensure your workspace is clean and that you have the right tools for the job.
Handle with Care: Grasp the spark plug boot and gently rotate it 90° counterclockwise. Pull the boot and cable away from the plug.
Pro Tip: If the boot is stubborn, use a dedicated removal tool. Never grab or violently pull the spark plug cables, as this can damage the internal wiring.
Clear the Debris: Use a brush or compressed air to blast dirt away from the spark plug well areas before removal.
Safety First: Always wear protective goggles when using compressed air to prevent eye injury from flying debris.
Cool Down for Aluminum Heads: If your engine has aluminum cylinder heads, allow it to cool completely before removal. Removing a hot plug from a hot aluminum head can lead to stripped threads.
Organizing your old plugs can tell you a lot about your engine's health.
Track Your Plugs: Place each removed spark plug in a tray labeled by cylinder number. This helps you identify if a specific cylinder is running lean, rich, or oil-fouled.
Signs of Failure: Inspect for technical defects such as:
Cracks in the upper or lower insulator.
Chipped or broken insulator tips.
Damaged or brittle spark plug boots.
The difference between a perfect tune-up and an engine misfire often comes down to the details.
The Dielectric Advantage: Apply dielectric grease to the inside of the boot area. This reduces the risk of "tracking" (electrical arcing) and promotes efficient heat transfer between the terminal screw and the boot.
Check the Gap: Use a precision gap guide to verify the clearance before installation.
CRITICAL NOTE: ACDelco GM OE Iridium Spark Plugs are pre-gapped at the factory. Never attempt to gap an Iridium plug, as you may damage the delicate electrode. If the gap is incorrect, replace the plug entirely.
Torque to Spec: Hand-tighten the plugs first to avoid cross-threading, then use a torque wrench to tighten to the manufacturer's specific torque rating.
| Feature | Best Practice |
| Removal Rotation | 90° Counterclockwise |
| Cleaning Method | Compressed Air (with eye protection) |
| Head Compatibility | The engine must be cool for Aluminum Heads |
| Lubrication | Dielectric Grease in the boot area |
| Iridium Plugs | Pre-gapped, no need to adjust |
FITMENT | 2012-2015 Camaro- 2006-2013 Corvette - 2009-2015 Cadillac CTS
WARNING: Cancer and Reproductive Harm -- www.P65Warnings.ca.gov
