Spark plugs play a crucial role in the car functioning because your car counts on them to start and run smoothly. A spark plug is preliminarily a high-voltage bridge to carry electricity. When electricity travels across the bridge (a gap between two contact points) and reaches the car engine, it generates a spark and ignites gas vapors, which start the engine. There are a lot of factors which determine how long your car spark plugs will last without needing a change. Your driving habits, the kind of fuel you use and the state of your car engine are important factors. Replacing spark plugs is easy and new plugs are not very expensive either. However, you should know when to change spark plugs and wires so that you do not end up causing any major damage to the car engine. Car manuals come with instructions on the same. You can follow certain simple car checks, as discussed further, to find out the right time for a spark plug change.

Why to Change Spark Plugs

Before learning when to change spark plugs, it is important to understand why to change spark plugs. New spark plugs help in maintaining optimum engine performance and efficiency. A car engine does misfire once in a while, but if the misfiring increases, engine power is affected and more waste gases are emitted. New cars come with a ‘Check Engine’ light which illuminates whenever there is an ignition problem with the car engine. To reduce instances of engine misfire and to maintain its optimum performance, it is important to change spark plugs as and when they wear out.

Starting your car in cold weather conditions can be a menace. And especially if you have a poor spark plug. As the spark plugs do not ignite even after several attempts, there are chances of your car battery running dead when the engine cranks. On such occasions, it is important to check your spark plugs and if it is worn out, replace it. A new spark plug will definitely improve cold weather starting, and also reduce the amount of voltage required by the ignition system.

It takes only a single engine misfire to deposit enough raw fuel into the exhaust, which will consequently overheat and harm the catalytic converter. The operating temperature of the converter rises when high amount of unburnt fuel enters the exhaust, leading to a partial meltdown of a substance in the converter. This can cause the car engine to choke. In such cases, you will have to replace the converter as well as the spark plug, to prevent the new converter from meeting the same fate.

How to Know When to Change Spark Plugs

Check your car mileage. Your car engine performance becomes less efficient when spark plugs are worn out and corroded due to carbon deposits and burns. This results in low gas mileage. In case you notice that your car is consuming more gas than it usually does, it could be time to change the spark plugs.

At times, you may experience some trouble while starting your car in the morning. Though this could be because of dirt accumulated in the fuel injectors, there are chances a faulty spark plug could also be a contributing factor.

Ideally, spark plugs in a car need replacement every 30,000 to 40,000 miles, depending on your car. You need to find out when was the last time you changed the spark plug in your car. In case you are not sure of the exact date, you can manually check by removing the spark plug and looking for excessive wear and tear or carbon deposits. Replace it, if necessary.

A rough running engine, slow response from the engine when you push the accelerator or the ‘Check Engine’ light illuminating on your dashboard could be signs that it is time to change spark plugs in your car.