How to Supercede Spark Plugs in Your Car

Salve big on automobile maintenance costs by irresolute spark plugs yourself!

Time

A few hours

Complexity

Beginner

Cost

$xx-50

Introduction

Changing spark plugs takes about an hour (for a four-cylinder engine) and will save you at least a hundred bucks in labor if you lot practice it yourself. In most cases information technology'southward a unproblematic job that volition assistance to maintain meridian performance and the highest possible gas mileage.

Tools Required

Materials Required

  • Anti-seize compound
  • Dielectric grease
  • Spark plugs

Projection step-past-step (7)

Step i

Why Do Spark Plugs Need to Exist Changed?

When a spark jumps the gap between two electrodes, it actually burns off (erodes) small amounts of metallic from each 1. Over time, the gap grows to the bespeak where the spark tin can no longer make the jump. That'southward when you get misfires, lower gas mileage, poor dispatch and, ultimately, the dreaded "Check Engine" light.

When to Check & Modify a Spark Plug

Not all spark plugs are rated for 100,000 miles. In fact, some carmakers recommend replacement at 30,000-mile intervals. Always follow the spark plug service intervals shown in your owner'due south transmission to effigy out when to replace spark plugs. Simply if you can't remember when you last changed your spark plugs, you tin pull them and bank check the gap and their condition. One time you've put in the labor to brainstorm checking spark plugs, however, you lot might likewise change them and plant a new baseline for the time to come.

Check out our favorite auto diagnostic tools for DIYers here.

Signs of a Bad Spark Plug

Unlike manufacturers' guidelines for oil changes, which are overly cautious, the recommendations for how often to change spark plugs tend to be overly optimistic.

For example, if you've already got lxxx,000 miles on a gear up of 100,000-mile plugs, they're fourscore percent worn and kickoff to have a toll on engine performance and gas mileage. Worse yet, after that many miles there is enough of spark plug vesture, and spark plugs tend to seize in the cylinder caput.

Removing a seized plug can be plush, especially if the threads in the cylinder head are damaged. Then what are the benefits of changing spark plugs? When you consider the gas mileage falloff and the possibility of seized plugs, early replacement makes sense.

Practice it Yourself or Have information technology to a Pro?

The answer depends on the blazon of engine in your vehicle. Some Five-6 models crave removing portions of the intake manifold to replace the spark plugs. If y'all're non comfortable with that, take your vehicle to a pro. But if your engine affords easy access to the rear depository financial institution, you tin probably do the job yourself. Merely be sure you gap the spark plugs properly and use a torque wrench.

The tools shown are available at online suppliers and motorcar parts stores. While y'all're there, ask the clerk for the spark plug gap and torque specifications for your vehicle. And buy a small-scale packet of dielectric grease. It's also important to ask about spark plug replacement price before making an appointment.

Step 2

Open Up and Clean Your Work Area

Starting time past removing the plastic "vanity" cover (if equipped) and the air cleaner assembly from the tiptop of the engine.

  • Label any vacuum hoses you lot remove and then you restore them to the right place.
    • Pro tip: Learn the acme of a four-cylinder engine, or the banks on a "V" engine, before you remove other parts.
  • Blast compressed air around the ignition coils to prevent crud from falling into the cylinders. Then accident any remaining loose dirt off the engine before you set out your tools and new plugs.

change spark plugs

Pace 3

Remove the Ignition Scroll and/or Boot

  • Disconnect the ignition curl electrical connector by depressing (or pulling upward) on the locking tab.
  • Rock the connector off the whorl.
  • Remove the ringlet concur-down bolt and pull out the unabridged whorl and kick assembly.
    • Pro tip: Some COP systems have a detachable rubber kicking and jump. If they don't come out with the gyre, retrieve them with needle-olfactory organ pliers and supplant them with new parts. And then remove the old spark plug.

If your machine doesn't have COP ignition, the spark plug wire will finish in a kicking that attaches to the spark plug. A spark plug wire puller makes it piece of cake to pull the boot off.

change spark plugs

change spark plugs

Step 4

Unscrew the Plug

  • Accident abroad the dirt and grime that's settled on and around the plug since it was installed.
  • Slide the proper size spark plug socket over the plug.
    • Pro tip: A swivel head spark plug socket makes the task much easier. You'll probably need an extension of some length to reach the plug.
  • Rotate the plug counter-clockwise to loosen it.
    • Pro tip: Non all engines leave the plugs every bit accessible every bit shown here. The more compact the engine compartment, the harder it will be to go to the plugs. But all plugs can be removed.

change spark plugs

Step 5

How To Gap a Spark Plug

Gap all plugs before installation using the manufacturer'due south specs. Always cheque the spark plug gap before installing information technology.

  • Slide the correct wire approximate (or gap gauge) between the electrodes. The wire should drag slightly betwixt them.
  • If the gap is too small, open it with the gap approximate by prying up.
  • If the gap is besides large, tap the side electrode lightly on a solid surface.
  • Place a small dab of anti-seize chemical compound on the plug threads and hand thread the plug into the cylinder head.

change spark plugs

Footstep 6

Install the New Plug

Proper spark plug torque is critical in today's engines.

  • Always use a torque wrench and the manufacturer'south spark plug torque specs. Bereft torque tin can effect in a plug blowing right out of the cylinder head, taking the threads with information technology. Besides much torque distorts the plug.
  • If yous used anti-seize compound on the plug threads, reduce torque past ten percent. If you don't have a torque wrench, become to the spark plug manufacturer's website to find manual tightening techniques and spark plug torque specs.

change spark plugs

Stride 7

Lube the Spark Plug Boot and Button It Up

  • Apply a thin coating of dielectric grease effectually the inside of the spark plug boot earlier reinstalling the coil. The grease prevents misfires and makes it easier to remove the boot in the future.
  • Reinstall the ignition coil, hold-downward bolt and coil electrical connector.
  • Reinstall the air cleaner and vanity encompass and fire it upwardly.

Note: Follow the same procedure for non-COP ignition arrangement boots.

change spark plugs

Originally Published: February 14, 2022