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FAQ

Got a question about your Autolite® spark plugs or spark plugs in general? Chances are that we’ve been asked that question a lot. Check below for a list of Frequently Asked Questions.

My dealer claims Autolite® plugs voids the warranty. Is this true?

If your local dealer is making a vehicle warranty contingent upon the use of their products, there may be a violation of Federal Law. As stated in the current Autolite® catalog as part of the Magnuson-Moss Warranty Improvement Act, "Using Autolite® or other quality brand name spark plugs does not void vehicle warranty". Magnuson-Moss warranty information is also available in the document titled "It's the Law". This document is in Adobe pdf format. If you need the Adobe Reader that is required to read the Adobe pdf format, it is free to download from get.adobe.com/reader/. Download and install the Adobe Reader, return to the Autolite® website, and refer to the documents.

You may also want to refer to the Federal Trade Commission Web site: www.ftc.gov for detailed information on the Magnuson-Moss Warranty Improvement Act.

How often should I replace spark plugs?

Autolite® following the recommendations of the vehicle manufacturer. Autolite® spark plugs should be replaced at least as often as the vehicle manufacturers recommended change interval. We always recommend that you replace Autolite® spark plugs with the same metallurgy as your OE plug or upgrade to iridium. We suggest you refer to your vehicle owner's manual, local vehicle dealer, or refer to a reputable automotive service facility for information on appropriate mileage service intervals.

How do I remove my spark plugs?

Spark plug installation may require the removal of engine components and may require that specific vehicle manufacturer procedures be followed to ensure proper service and safety. It is recommended that you follow the instructions listed in the vehicle service manual or as instructed by your local vehicle dealer or a reputable mechanic for specific spark plug service and replacement.

Quick Tips on Changing Your Plugs:

  • The Autolite® brand recommends that do-it-yourselfers follow manufacturer's recommendations on spark plug change intervals. It is good maintenance procedure to change all the plugs simultaneously.
  • Always be sure the engine is cool before beginning and gather all essential tools and products needed for the change, including replacement plugs, spark plug socket & ratchet, and mechanics gloves.
  • Rotate boots 90-180 degrees before attempting to pull them off. This helps break the boots loose without tearing. Do not pull on the wire.
  • Before removing the old spark plugs, clean debris from the side of the plug area by using air pressure (use a shop vacuum). This helps prevent any debris from falling into the cylinder and causing engine damage.
  • Look at the old spark plug tips to see if the engine has a problem that needs correcting.
  • When gapping new plugs, use a round, or loop, feeler gauge. It will give you a more accurate reading and will also help extend the life of the spark plug.
  • If having a hard time installing plugs, installers should use a piece of hose to extend their reach.
  • After final assembly, visually look to make sure all wires are properly routed so that they are not lying on the hot manifold or in the way of other objects that can cause damage.

If you have any questions regarding your Autolite® spark plugs, reach out to Autolite’s Customer Service to consult with one of our technicians: 1 (800) 890-2075. You can also submit an inquiry through our Technical Support chat form located in the lower right corner of the page.

What is the function of a spark plug?

The spark plug is an integral part of the ignition system with its primary function is to generate a spark from the C.E. (center electrode) to the G.E. (ground electrode).

This spark is used to create heat to ignite the air/fuel mixture within the cylinder creating the combustion to force the piston downward causing the crankshaft to turn and create torque and power ultimately turning the wheels.

Spark plugs must endure severe temperatures, pressure, high voltage, and other factors that demand a lot from a plug to perform at a high level constantly over a long period of time.

What are the different types of spark plugs?

Spark plugs are available in different metallurgies, designs, and specifications. The variations are required to match engine requirements and provide alternative performance benefits. Since the 2000’s OE’s have primarily used iridium plugs to meet their performance needs. It is important to understand the needs of your vehicle when identifying replacement spark plugs.

How do I "read" a spark plug?

You “read” a spark plug by looking at the firing tip of your spark plugs. You want to look at the condition and coloration of the ceramic insulator and the metal electrodes (known as the center wire and ground wire). Observe the color first. Light tan or gray deposits are normal, and an indication that everything is working well. If everything is very white, with glazed deposits on the insulator tip, the spark plug is too hot for the engine, or at least for the conditions for which it was used. If black sooty deposits are present, a too rich fuel mixture is likely, or the spark plugs' heat range may be too cold for the application. Shiny black or oily deposits are an indication of bad oil seals and/or piston rings, and are not an indication that the spark plugs are at fault. Click here for more information. Let our technicians help you at Autolite® Answers (SM). 855-200-5200

How (and why) do spark plugs need to be tightened for best performance?

It is very important to properly tighten spark plugs during installation. Too little torque can cause the spark plug to leak combustion gases and poor heat transfer of the plug seat to the cylinder head. Over-torque can damage both the spark plug and the threads in the engine head. Both can cause extensive engine damages. Your Autolite® Catalog lists the proper torque specs for various spark plug sizes. Check here for more information.

How long do spark plugs last?

Spark plug lifespan varies depending on a variety of factors from metallurgy, engine & plug design, and driving habits. There are advantages to using precious metals and center & ground electrode enhancements and designs. Use in some engines this will provide superior performance and in others provide the performance needed for your engine to perform as designed. Using plugs with lower quality materials or standard designs will impact performance and life. Always check your vehicles owner's manual to make sure you are using the right parts and replacing them at the right frequency to ensure engine health. 

Do Autolite® spark plugs come pre-gapped from the factory?

Autolite® and all spark plug manufacturers offer spark plugs pre-gapped in the most popular gap sizes. Because of the many gap sizes required, no one offers spark plugs properly gapped for every application. It should always be checked and adjusted as necessary at the point of installation to ensure proper performance. You can be sure that the Autolite® spark plug recommended for your application has been engineered to meet the requirements of your engine, and that the gap can easily be adjusted as required.

What does it mean when spark plug tips are damaged or broken?

Spark plug tips, either the electrodes or the ceramic insulator, can be damaged in a variety of ways. Damage such as cracked ceramic or bent electrodes can be the result of shipping and handling, from mishandling and improper adjustments, or from mechanical damage within an engine. If an incorrect spark plug is used, it could come into contact with a piston or valve within the engine. Spark plugs can also be damaged by detonation or pre-ignition while in service. Click here for more information.

What is a fouled spark plug?

Spark plugs can become "fouled" by excessive fuel, oil or combustion deposits in the combustion chamber. Essentially what this means is that the spark plug insulator tip has become coated or covered by deposits which can conduct electricity. The spark plug has become "short circuited". In other words, the electrical current will now flow from the center wire over the insulator's deposits, to ground at the steel shell. It will not be able to produce a spark at the electrodes. Click here for more information.

How do you match the style and heat range of the OE spark plug?

We use what is called a "rating engine" to match up plugs. The process begins by buying the OE spark plugs and carefully measuring them. Our engineers then match the physical qualities with several Autolite® plugs. Then we run the OE spark plug in our rating engine. The data from this engine tells us the heat range of the OE spark plug. We use this information to precisely match an Autolite® spark plug to both the heat range and dimensions of the Original Equipment plug.

What are the benefits of using a  Finewire Iridium Enhanced spark plug that originally had a different metallurgy or non-finewire design?

  • Iridium finewire designs are engineered to offer improved ignitability and durability over a standard designs or other metallurgies.
  • More focused ignition to prevent fouling than standard plug
  • More horsepower and better fuel efficiency than standard plug
  • Larger flame kernel for more complete burn, faster starts and better performance & fuel efficiency
  • Optimum Performance
  • Less firing voltage for more coil dwell time

Can I use an Autolite® Xtreme Sport Spark Plug in my 2-stroke engine?

Yes you can, it will give you up to 26% quicker starts than leading standard plugs and better ignition system performance. The benefits of the finewire design in Autolite® Xtreme Sport also provide improved fouling performance; fouling is a common problem in 2-stroke engines.

Do diesel engines have spark plugs?

No, diesel engines do not have spark plugs.  Diesel engines use glow plugs which create ignition using temperature instead of creating a spark. It is always important to reference your owner’s manual or parts specialist to ensure you are using the proper equipment for your vehicle.

Are spark plugs / glow plugs universal?

No, spark plugs, and glow plugs are not universal. They must match your vehicle's specific engine requirements. There are many technical specifications that make plugs unique to certain applications to ensure proper fit, form, & function. Always refer to your owner's manual or consult a parts specialist to find the correct spark plugs for your car.

What is the Autolite® National Rebate Program and how can I submit a claim?

Our national rebate program runs from January 1st - December 31st and consists of the following offerings: $3 per Iridium Ultra plug, $3 per Iridium XP plug, $2 per Double Platinum plug, and $1 per Glow plug. To learn more about the program’s terms and conditions, or to submit a rebate claim online or access the mail-in rebate form, please visit: https://www.autolite.com/resources/rebates/