How to Change Your Spark Plugs

Spark plugs are a small but mighty car part. They’re usually less than an inch long, but without them, your engine wouldn’t start. In this blog post, we’ll explain what spark plugs are, along with how and how often to replace them.

how to change your spark plugs - comment remplacer vos bougies d allumage

What Are Spark Plugs?

Spark plugs are used in internal combustion engines (ICEs), which are powered by gas. As their name suggests, they create sparks, and those sparks are necessary for an ICE to run.

A gas-powered engine contains valves, pistons, cylinders, and spark plugs. The valves fill the cylinders with air and fuel, which are highly combustible when combined (hence the term internal combustion). The pistons compress this mixture.

At the highest point of compression, the spark plugs ignite the air and fuel, creating a controlled explosion that powers the engine.

When to Replace Them

Believe it or not, spark plugs can usually withstand millions of these explosions before wearing out. If you have your vehicle’s original spark plugs, check your owner’s manual for replacement recommendations. Normally, we recommend replacing your spark plugs every 30 months or 48,000 km (whichever comes first). However, some spark plugs—for example, those made of iridium—can last as long as 160,000 km.

Visit www.NAPACanada.com to search for spark plugs. Enter your vehicle specifications to get a guaranteed fit. We sell not only NAPA spark plugs but also spark plugs from NGK, Bosch, Champion, Autolite, and many other high-quality aftermarket manufacturers.

How to Replace Spark Plugs

Before You Start

It’s important to allow your vehicle’s engine to cool completely, especially if it has aluminum cylinder heads.

You should also follow these essential safety rules anytime you do work on your vehicle:

  • Have a first-aid kit handy.
  • Be careful when working around hot or sharp objects.
  • Follow the manufacturer’s instructions for all products.
  • Use safety stands under the vehicle’s frame or drive-on ramps if you have to raise your vehicle.
  • Ensure you have proper ventilation before you turn on the engine.
  • Don’t smoke when working around the engine.

What You’ll Need

Gather the following tools and items so you can complete the task in one go:

Spark Plugs

Starting at 4.39 $

Buy Now

Kohler Spark Plug Wrench

10.99 $

Buy Now

 

Spark Plug Gap Gauge

Starting at 5.59 $

Shop Now

Torque Wrench

Starting at 33.19 $

Shop Now

Installation

Read these instructions completely before you begin.

You’ll need to purchase new spark plugs that are the right size and heat range for your vehicle’s engine. You can find these specifications by checking the manufacturer’s recommendation or by using our spark plug selector on www.NAPACanada.com.

Adjust the Gap of the New Spark Plugs

Most spark plugs these days have preset gaps, so you don’t have to adjust them. If your spark plugs need to be adjusted, here’s what to do:

  • Look up the correct gap for the new spark plugs in your vehicle’s owner’s manual.
  • Choose the correct measurement on yourand insert the gauge between the inner and outer electrodes at the tip of the plug. When the plug is properly gapped, the wire or feeler should slide between the electrodes with a slight drag. If the gap is incorrect, gently bend the outer electrode slightly until you’ve achieved the correct gap.
  • Make sure that the outer electrode is centred directly over the inner electrode. If the electrodes aren’t aligned, gently bend the outer electrode until it’s in position.

Remove the Old Spark Plugs

Remove and replace the old plugs one at a time or use tape to label each wire so that you don’t mix them up.

  • Once the engine has cooled, pull the rubber boot to carefully remove the spark plug wire from the end of the spark plug. Do not pull the wire itself. If the boot sticks, use a twisting motion to pull it and the plug wire free.
  • If you have access to compressed air, use it to blow away any dirt from the spark plug area. Otherwise, clean off the old plug and the area around it with a rag or small brush. This will help keep foreign material from falling into the cylinder when you remove the plug.
  • Remove the plug by turning it counter-clockwise with a spark plug wrench or a spark plug socket and ratchet. If the plug is hard to remove, use a small amount of penetrating oil.

Check the Cylinder Head Threads

  • Visually inspect the cylinder head threads. They should be in good condition, clean, and free of dirt and debris. Each new spark plug should be easy to screw into the cylinder head by hand. If any of them binds up, you have a problem. Remove the plug and inspect the threads.

Install the New Spark Plugs

  • Make sure that the area around the spark plug port is clean, and wipe the seat with a clean rag. You want to ensure proper contact between the new plug and the seat.
  • Insert the plug into the spark plug hole by hand and turn it clockwise until it’s snug. If the spark plug hole is hard to reach, attach a short piece of 5/16-inch rubber hose to the top of the plug to create a kind of extension.
  • After screwing in the plug by hand as far as it will go, firmly tighten it with a spark plug wrench or socket. If you have a torque wrench, it’s a good idea to use it. Using a torque wrench will ensure the plug is properly seated. Do not over-tighten. And remember: the only way you’ll get an accurate torque reading is if the spark plug and cylinder head threads are clean and dry.
  • Reattach the plug wire to the new plug and use a twisting motion on the boot until it’s firmly seated on the top of the plug.
  • Repeat the above steps for each plug you’re replacing.
Install the new spark plugs - installation des nouvelles bougies

It’s easy to blame the alternator or battery when your engine won’t start, but the fault could also lie with worn spark plugs. Complete these tests to rule out other engine issues first. If you’re nearing the recommended time to replace your spark plugs, then changing the bad ones out before you experience engine problems is also a good idea.

As usual, if you have any questions about spark plugs, the experts at our NAPA Auto Parts stores would be happy to help!

Leave a comment

Your email address will not be published.Required fields are marked *