In order to operate, your engine needs fuel and air. However, those two things alone won’t make it run. It needs a way to ignite the fuel after mixing it with air from the intake. That’s what your car’s spark plugs do. They create an electrical spark (as the name implies) that ignites the fuel/air mixture and runs your engine.

Spark plugs have advanced quite a bit from what they were a few decades back. You’ll find a host of different types on the market, from dual and quad tips to iridium tips and many more. The primary reason that spark plugs need to be changed is due to wear and tear. As the spark plug fires, minute amounts of the electrode evaporate. Eventually, it’s too short to create the spark needed to ignite the fuel/air mix. The result is a rough running engine, skipping cylinders and other problems that cost you in performance and fuel economy.

In terms of lifespan, the use life you enjoy will depend in the type of plug used in the engine. Normal copper plugs only last about 20,000 miles. However, using platinum plugs can give you 60,000 miles of use. Other types can last up to 100,000 miles.

Of course, it can be very difficult to tell if your spark plugs are beginning to wear out. They’re installed in the engine, so checking the wear isn’t as simple as it is with other things, like your tires. However, there are several key signs that you can watch for that indicate your engine’s spark plugs are nearing the end of their life. These include:

  • Rough idling (which can also be a symptom of many other problems, but worn plugs should be eliminated as the cause)

  • Poor fuel economy (another multi-problem symptom, but spark plugs are a common reason)

  • Misfiring engine

  • Lack of power when accelerating

  • Engine surge (caused by too much air in the air/fuel mixture, often due to worn spark plugs)

If you suspect that your car is in need of new spark plugs, YourMechanic can help. One of our mobile mechanics can come to your home or office to inspect the plugs, and replace them if needed. They can also inspect other ignition system components, including spark plug wires, coil packs and more to ensure that you can get back on the road quickly and safely.

This article originally appeared on YourMechanic.com as How Long Do Spark Plugs Last? and was authored by Valerie Johnston.


Share This Photo X