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M103B Full Set of 8 Ignition Coils (Interchange # DG521)

Availability: In stock


Quick Overview

This product includes FREE SHIPPING & ships on the same day if ordered by 3:30 pm PST (6:30 pm EST) Monday-Friday.

QTY: 1 = 1 set of 8. This is a set of 8 brand new quality Araparts brand quality ignition coils for your vehicle. These are also known as Coil on Plugs, or COPs. This set comes with a pack of 2.5g silicone dielectric grease, and a LIFETIME WARRANTY against defects. They also use copper windings, just like the original equipment. 

This is for a FULL SET of 8 (eight) coils). This set ships for free VIA USPS 2-3 day air to ALL 50 states. This includes Saturday delivery. At, all of our ignition coils are manufactured private label for us and tested after the manufacture process to ensure the coil is fully operational. If you have a defective coil, we will pay to return it, and send a replacement over. Easy as a snap. Most people with old or misfiring coils notice a significant improvement and restoration of vehicle performance and fuel economy.

Part Number: M103B (with the brown boots)

Part number interchange:

  • DG521

  • 8L3Z12029A


The listing you are viewing is for a complete set of 8 Araparts brand coils. If your ignition coils are several years old, it is recommended to replace all at the same time for improved performance. New coils are a major factor when it comes to restoring vehicle performance, and gas mileage. We are able to get our prices so low by purchasing several hundred, and even several thousand coils at a time, when your local auto parts store may only purchase 4-10. We are not a drop shipper. We have a physical location in Northern California.

Internal Windings Material: Copper
Boot: Silicone

Guaranteed to fit - Scroll down to view fitment information - Many of our customers are concerned if the ignition coils will fit their vehicle. Here at Araparts, we provide all information you need for your vehicle fitment. When buying from Araparts, you can be assured that you have the correct part for your car. We provide all of the fitment information we can, but if our fitment information is incorrect, we will pay to return the coils that don't fit. We make it work to where you can't lose. We are always working every day to ensure that all of the fitment information is spot on.

Buying autoparts online is a new concept to many people, and you're not alone. We're here to build the bridge that connects you, and the EXACT part that you need.


Make sure it fits!!

Important note for ALL 2008 models.  2008 was the year that Ford, Lincoln, and Mercury changed the boots from the short black ones to the longer brown ones. Some 2008 models have the black boots. It is easy to identify which color the boots are by opening the hood and taking a look at the coils that are in the front of the engine. You will be able to see the boots without removing the coil.


  • 2008-2014 FORD EXPEDITION 
  • 2008-2010 FORD EXPLORER 
  • 2008-2010 FORD F-150
  • 2008-2010 FORD F-250 SUPER DUTY 
  • 2008-2010 FORD F-350 SUPER DUTY
  • 2008-2016 FORD F-450 SUPER DUTY 
  • 2008-2016 FORD F-550 SUPER DUTY
  • 2008-2016 FORD F53 
  • 2011-2016 FORD F59 
  • 2008-2010 FORD MUSTANG
  • 2008-2014 LINCOLN NAVIGATOR 











More information about these:

Ignition Coils for Your Ford, Lincoln, or Mercury (DG521 interchange):

The DG521 style coil is a two pin coil with brown rubber boots as opposed to the older style that is exactly the same, but with shorter black rubber boots.An ignition coil (also referred to as coil pack, coil on plug/COP, coil over plug)  is a crucial part of your ignition system. An ignition coil is an open circuit miniature power transformer. The DG511 style coils have a resistance of 5.5 ohms and convert the 12v in your Ford electrical system to 35,000 volts, which is the same as the original coil. This will send the voltage to the spark plug, and ignite the fuel. Ignition coils wear out over time. High and low temperatures, humidity, and even bad grounds and electrical problems can cause ignition coils to fail, or not perform at full capacity. This can cause a misfire, also referred to as hiccups or surging.

Replacing all 8 ignition coils at once

Because the ignition coils wear in the same environment, it is usually best to replace old ignition coils all at the same time, and save money or time on labor. Other causes are washing the engine bay, and rain. The DG521 style ignition coil is a commonly replaced item in most of the Ford cars, trucks and SUV. In some instances of minor misfiring on Ford Lincoln or Mercury vehicles, the check engine light will not illuminate. This is because the PCM does not illuminate a check engine light unless the misfire is more than 2.3% of the firing time. It does however still record the misfire. We can help you find these for FREE in our how-to section.

Checking vehicle grounds, wiring, and other components such as the vehicle computer (also referred to as the PCM, ECU, or ECM) can also prevent repeated failure of ignition coils and save hundreds, or even thousands of dollars in repairs.

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All of our parts come standard with an unlimited mileage warranty. The warranty length is shown on each product description page. We will repair or replace any defective part free of charge, and we'll even pay for return shipping for defective parts. Most other companies will not pay return shipping. 


Why are your parts so cheap?

What makes us very different from your local auto parts store and dealership is volume. We are a small company, but whatever item we carry, we carry hundreds, or even thousands of. This allows us to get that same quality auto part as your local aftermarket auto part store, but at a fraction of their prices. 



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