How To Change Spark Plugs

Keep the engine in good condition. Here’s how to replace spark plugs. Save big on car maintenance costs by changing spark plugs yourself!

Replacing worn spark plugs can greatly improve engine performance and efficiency. The replacement interval varies depending on the car manufacturer and the metal type and design of the spark plug. The recommended spark plug replacement interval ranges from 35,000 miles to every 120,000 miles. You need to follow the recommendations in the user manual. Can be upgraded, but never lower than the manufacturer’s factory requirements. Doing so will hinder performance and may cause issues related to sister components or the engine itself.

Spark plugs continue to catch fire and wear out over time, reducing efficiency. On some automotive engines, the replacement of spark plugs can be challenging. The biggest challenge you will face is accessibility and sticky parts, such as when removing the spark plug wire or ignition coil/dust jacket and loosening the spark plug. Some spark plugs may be difficult to reach, and the upper air chamber/intake manifold needs to be removed. In these cases, a new inflatable cushion will be required—view maintenance guides for specific vehicles and engines.

What Does a Spark Plug Do?

How To Change Spark Plugs-Auto Guides

First you need to understand what spark plugs do? In short, they create a spark of electricity that ignites the fuel and drives the pistons of the car, eventually starting the car.

You already know that the spark plugs are wearing out. Well, “burning out” is more similar because when a spark jumps through the gap between two electrodes, it actually burns (erodes) small amounts of metal from each of them. Over time, the gap increases to the point where the spark can no longer jump. Then there are misfires, poor gas mileage, poor acceleration and, ultimately, the frightening “Check Engine” light. Read on to learn how to replace spark plugs. We will also explain when to replace spark plugs and how often to replace spark plugs.

To maintain maximum vehicle performance over extended service intervals, many car manufacturers are installing long-life spark plugs. Because their electrodes are coated with precious metals with higher melting points, these plugs can sometimes maintain a precise gap of up to 100,000 miles. But even at higher melting points, metals such as yttrium (2780 degrees F), platinum (3221 degrees F) and iridium (4430 degrees F) are not able to prevent erosion forever. The electrodes eventually erode, increasing the gap and, well, you’ve heard the rest of the story.

If you’ve changed your own spark plugs in the past but are intimidated by new plug-in ignition coils (COPs) (almost standard since 2000), it’s time to think again. COP systems may look complex, but in reality they are easier to work than older systems based on distributors. Sure, you need to learn some new tricks, but the basics are the same.

How to Replace a Spark Plug

Replacing the spark plugs takes about an hour (in the case of a four-cylinder engine) and will save at least one hundred bucks of labour. You can use the same old adjustment tools (ratchet, spark plug socket and feeler gauge). Use a torque wrench to tighten the end caps.

In some people’s eyes, the car’s engine seems to be a complex job impossible for a mysterious machine. Although this is not too far for many modern engines, even the most high-tech cars still have some easy-to-maintain items. The spark plug, in particular, is one of the easiest parts to replace in any given engine. All it needs is to carefully follow some basic steps and some basic tools.

Allow the car engine to cool before replacing the spark plugs. This will make it easier to remove the spark plugs and spark plug wire or the ignition coil cover.