How Often Should You Change Your Spark Plugs?
Like that random guy outside the bar, your engine needs a light.
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An automobile engine needs gas, air, and spark to get its internals chugging along like our childhood pal Thomas. Without any one of these, the engine will falter and you won’t be making it up that hill.
While the automotive industry shifts toward fully electric vehicles at this very moment, internal combustion engines have relied on a strike of electricity all along. The spark plug is responsible for creating a car’s all-important spark to ignite the gas and fuel mixture, and if it’s damaged or incorrectly set, it can lead to a malfunctioning, or dead-as-a-doornail, car.
Spark plugs do require maintenance and replacement, but there’s no specific rule of law as to when they need servicing. It’s up to you, the owner, to regularly check your plugs and to recognize signs of a faulty plug. The Drive’s callused info team will show you how.
What Is a Spark Plug?
A spark plug is a small device that plugs into the engine, more specifically into the cylinder, and provides the spark for combustion via a conduit connecting the battery to the spark plug. A household consumer engine typically has as many spark plugs as there are cylinders, so an inline-four has four plugs, and a V8 has eight plugs. Some cars, however, feature two spark plugs per cylinder for more precise ignition.
Spark plugs are made up of a bunch of small parts that use copper, nickel, iridium, and platinum, among others. For protection and insulation, spark plugs also use ceramic.
What Does a Spark Plug Do?
A spark plug creates a small string of high-voltage electricity within a specifically measured gap between a center electrode and a ground electrode. This spark occurs within the cylinder and ignites the air and fuel mixture. This explosion pushes the piston back down the cylinder.
Symptoms of Faulty Spark Plugs
If a car’s spark plugs are fouled, improperly gapped, or dead, it could exhibit one or more of these symptoms:
- Car won’t start or struggles to start
- The car idles poorly
- Engine knocking or pinging
- Worse-than-normal fuel economy
- Suffering performance
How To Change Spark Plugs
With the correct tools, checking and changing spark plugs can be accomplished by even amateur DIYers! For a complete breakdown, check out The Drive’s step-by-step guide, How To Change Spark Plugs.
How To Gap Spark Plugs
For a spark plug to deliver precisely the right amount of electricity at the correct time, it needs to be gapped correctly. Spark plug gaps can be checked and maintained with a spark plug gap tool, and we’ve got you covered on that too. For more information, read The Drive’s guide, How To Gap a Spark Plug.
Get Help From a Mechanic On JustAnswer
Although The Drive’s detailed how-to guides are easy to follow, a rusty bolt, an engine component not in the correct position, or a messy oil leak can derail a project. That’s why we’ve partnered with JustAnswer, which connects you to certified mechanics around the globe, to get you through even the toughest jobs.
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FAQs About Spark Plugs
You’ve got questions, The Drive has answers!
Q: So How Much Does It Cost To Change Spark Plugs?
A: For commonplace consumer vehicles, a single spark plug will typically cost about $2-20. If you’re changing the plugs on a used Bugatti Veyron, well, be prepared to pay a little bit more.
Q: Ok, Then How Often Should Spark Plugs Be Replaced?
A: If you want to use a hard rule for changing spark plugs, rather than changing based on the condition of the plug, they should be serviced roughly every 30,000 miles. However, know that they might fail sooner than that, or a lot later.
Q: Should You Replace All Spark Plugs At Once?
A: Yes, as a general rule, it’s better to replace all plugs at the same time to ensure consistent levels of performance. No half-measures in this garage.
Q: But What Happens If You Don't Change Your Spark Plugs?
A: Driving with bad spark plugs could lead to poor performance, poor fuel economy, misfires, or your car might not even start. At worst, they could cause extra wear to your engine.
Q: And What Happens If You Don’t Gap Your Spark Plugs?
A: If the gap on your spark plug isn’t set to the correct specification, you might get misfires or knock or see carbon build-up or excess fuel. Always check if the gap is correct.
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