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25% Off All Online Orders of Select Parts and Accessories
Receive 25% Off Your Online Purchase. Use promotional code 25PEP at checkout to receive discount. Not valid in combination with any other discounts or promotions. Not valid on gift cards, special orders, installed merchandise, commercial or fleet purchases. Excludes the following categories: Tires, Wheels, Batteries, Powerstop Brake Kits, Oil, Antifreeze, Refrigerant, Truck Boxes, Vent Visors, Bug Shields and BRANDS: Razor, Traxxas, Superchips, Hypertech, Edge, Bully Dog, Diablo, Edelbrock, Holley, NOS, Proform, Specialty Auto, Thule, Autometer, Accel, K&N, Kenwood, Pioneer, Sony, JVC, MSD and BBK Performance. Valid online until 2:59 am EST on 12/12/16. Online orders scheduled for in-store pick up must be completed by closing on 12/11/16 for discount to apply.

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  • Part #: 41-121|
  • SKU: 921516

Available tomorrow after 1 p.m.

    • Iridium is one of the hardest metals used in spark plugs today, which allows for smaller, more efficient electrode designs for improved cold starting and quicker acceleration
    • Latest evolution in high-performance plug electrode material
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ACDelco Professional Iridium Sparkplug

ACDelco iridium spark plugs are the latest evolution in high performance plugs. The natural properties of iridium, with a melting point of approximately 700 degrees Celsius higher than platinum, help enable the plug to burn fuel more efficiently and to deliver better performance. As a result, the iridium plugs have a minimum service life of 100,000 miles (service life varies with individual driving conditions.) Since iridium is one of the densest materials found on earth, the iridium-tipped center electrode is 50 percent the size of a platinum electrode, and 20 percent the size of a conventional nickel electrode. The secondary micro-discharge of the center electrode burns off carbon deposits as they form, for superior anti-fouling performance that, along with the tapered cut-ground electrode, offers enhanced flame spread during combustion. The specially designed electrodes increase the electric field strength at the gap, reducing the voltage required for sparking to begin, for improved cold starting and quicker acceleration. The application coverage of ACDelco iridium spark plugs continues to grow, with the plugs being backed by a 100,000-mile limited warranty.
  • Iridium is one of the hardest metals used in spark plugs today, which allows for smaller, more efficient electrode designs for improved cold starting and quicker acceleration
  • Latest evolution in high-performance plug electrode material
  • Improved cold-starting and acceleration characteristics
  • Reduced ignition system voltage demands saves wear and tear
  • New-vehicle applications using iridium plugs continues to increase
  • 100,000 miles/Unlimited months WARRANTY (parts only)
ACDelco Professional Iridium Spark Plug

Electrode Core
Electrode Tip
Thread Size


Rated 4.7 out of 5 by 16 reviewers.
Rated 5 out of 5 by Only buy the best AC Delco plugs in GM products, period. These are top line and last forever. May 30, 2015
Rated 5 out of 5 by Hapy Install was easy! Runs and drive Good! Only downside was you have to gap them.. January 16, 2015
Rated 5 out of 5 by excellent spark plug for a great price. These AC Delco spark plugs are great i used them both in my GMC Envoy and Chevy Cavilier, I got better gas mileage and better performance. December 19, 2014
Rated 4 out of 5 by It's a spark plug Not much to say, it's a nice looking spark plug that works well. No problem with installation. December 2, 2014
Rated 2 out of 5 by Engine Performance My Cobalt has 61k I bought the new ACDELCO IRIDIUM sparkplugs, it seemed to help the engines power but after about three weeks, the power seems to be back to where it was before I installed the new plugs. Not sure what that's about?? October 23, 2014
Rated 5 out of 5 by product is standard replacement for 2006 Grand Prix (GXP) makes the car run like new again August 14, 2014
Rated 5 out of 5 by REQUIRED SPARK PLUG Do not know enough about this plug to make a comment only that it is required. August 12, 2014
Rated 5 out of 5 by 41-110 highly recommended for 5.3l vortec I replaced 748gg AC delco wires and 41-110 acdelco spark plugs also acdelco spark plug shields on my 2003 chevrolet suburban1500 ls 5.3l vortec Vin:z After 100000 miles and it runs as new again These new iridium spark plugs run smooth perfect match for my car. If you decide to change spark plugs use only AC Delco on Chevrolet . Used to have Bosh platinum and it run poor at low idle speeds July 7, 2014
  • 2016-12-08 T07:43:22.850-06:00
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