How Long do Spark Plug Wires Last?

Spark plug wires also known as the ignition wires are important components of a vehicle as they help in transferring current from the coil to the spark plug.

Any defect in the spark plug wires could cause the engine to misfire, thereby making driving inconvenient due to stalling, misfiring, and rough idling encounters.

For this reason, most car owners have the “how long do Spark Plug Wires last?” question on their minds with no straightforward answer.

But the right answer is that a spark plug wire doesn’t have a specified lifespan since I have seen car owners who used one spark plug wire for up to 1 – 15 years without any crack.

While some persons say the general spark plug wire lifespan is 60,000, 70,000, to 257,000 miles; it isn’t certified yet.

However, conditions such as high temperature will reduce the lifespan of the spark plug wires that’s why I’ll advise that you get a silicon-coated plug wire rather than a rubber-coated one.

Regardless, once you notice a crack or opening on the insulator then you’ve to install a new spark plug wire for safety reasons.

Having got an idea of how long a spark plug wire is supposed to last, let’s see the function of the spark plug wires and how to make them last longer.

How frequently should I Replace Spark Plug Wires?

If you’re using older vehicles then it’s advisable that you change your spark plug wires whenever you’re getting a plug replacement because plug wires on older vehicles have a mileage of around 60,000 to 100,000 miles.

Recommended:  How Much Gold Is In A Catalytic Converter?

Also, car owners who are fond of pulling out spark plug wires to check if it wraps around the spark plug are enhancing plug wire shortage or breakage.

Meanwhile, owners of new car models may not encounter faults in the spark plug wires until it is been sold out due to how modern spark plug wires are built.

This is because the modern vehicles and spark plug wires are routed and insulated properly making them durable.

However, there are a few symptoms that you’ll notice on your car that are susceptible to a spark plug wire shortage or failure. Example includes.

  • Engine stalling
  • The check Engine light will turn on
  • Engine misfiring
  • Crack in the spark plug wire insulators
  • Sparks coming out of cracked insulators
  • Rough idling and the current related issues

So, in conclusion; there’s no defined lifespan to use a spark plug wire, however, there are external factors that might affect the lifespan.

How to Check Spark Plug Wires

There’s a worthy way to test a spark plug which I saw on quora and I’ve tested it personally.

All you need to do is run your car engine at night when the darkness is optimal then watch out for a current(electricity) leak on the insulators that wrap the wires.

The main goal is to detect cracks and unrouted electrical current that’ll come in contact with metal parts of the engine thereby causing misfiring.

You can now use black tape to clothe the openings as a temporary fix. You can also get a spark plug wire replacement.


Spark plug wires are responsible for sending current from the engine coil to the spark plugs to enable proper engine functionality.

Recommended:  How to Clean Engine Valves Without Removing Head

While all components on a car often experience wear and tear, the spark plug wires stay exempted in modern vehicles due to their packaging.

Unlike older vehicles where you’ll need to often check to make sure your plug wires are intact.

Whichever the case may be, I’d recommend you get a spark plug wire replacement once you notice peeling on the sheaths covering the wires.

How helpful was this post?