What Is A Spark Plug and Why Is It Important?

Every internal combustion engine on Earth has a set of spark plugs, which are small cylindrical devices located on the top or side of the engine head.

Why Spark Plugs are the Core of the Combustion Process

VW Sparkplug

Have you ever wondered how the fuel inside the engine’s combustion chamber is ignited? It’s all because spark plugs create an actual spark inside the combustion chamber. The spark ignites the mixture of fuel and air, and creates a small controlled explosion. The explosion creates pressure in the cylinder and pushes the piston down to create power for the engine. Without spark plugs, the engine won’t run. Who would have thought such a small part was so instrumental to an entire engine’s operation?

What to Expect When a Spark Plug Fails

It’s very common for spark plugs to fail. In fact, almost every car owner has experienced or will experience spark plug failure. Spark plugs used to need to be replaced every 30,000 to 50,000 miles. Both spark plugs and engine design have improved, so many newer vehicles don’t require frequent spark plug replacements. However, spark plug failure is still common and every car owner should know how to identify it when it happens.

A few of the most common causes of spark plug failure are:

  • Erosion of the electrode due to normal wear
  • Fouling due to excess oil consumption (usually in older cars)
  • Breakage due to over-tightening when installed

Spark plugs generally last about half the lifespan of a car, so when your Volkswagen makes its 5th trip around the sun, either replace your spark plugs or start keeping an eye out for the following common symptoms:

  • Decreased fuel economy
  • Rough idle
  • Difficulty starting the vehicle
  • Sluggish acceleration

You can formally diagnose a failing spark plug by following the tutorial here.

How to Fix a Failing Spark Plug

Old spark plug

If you’ve determined that your engine has a bad spark plug or two, it’s time to replace them. It’s recommended that you replace all of your spark plugs at once to prevent any further issues. Spark plugs are cheap, and it's not too difficult to replace them. The savings from increased fuel economy can easily pay for new plugs.

First, buy OEM replacement spark plugs and then replace them using the tutorial here.

Got any questions about buying replacement spark plugs and/or replacing them? Feel free to contact us. Our dedicated team of experts will be happy to chat with you!