When Should I Change My Spark Plugs?


What Are Spark Plugs?

Ok, so back to basics.. All petrol powered cars need a spark to get the engine started, a spark plug is a component for delivering an electrical current from your ignition system (around 30,000 volts of electricity) into your cars combustion chamber to ignite the highly compressed mixture of fuel and air.

The spark plug is screwed into the engines cylinder head so that the electrode end is sat within the combustion chamber, different cars can have different quantities of spark plugs and you should change them all together to make it easier to keep track and for a consistent performance level.

When Should I Change My Spark Plugs?

Here are our top tips on when your spark plugs will need looking at or changing.

1. Your engine has a rough idle

Your engine idles when it is a stationary and in this position the engine normally shows around 1000rpm on the rev counter. The sound your engine should be constant and smooth but if your spark plugs aren’t working as they should, your engine will produce a rough and uneven sound, leaving your spark plugs in this state could lead to costly damage being done.

2. Are you having trouble starting your car?

Many people put their car not starting down to being out of fuel, cold or having a flat battery, one cause that you may overlook is having worn or faulty spark plugs. It’s also possible that faulty spark plugs are causing your car battery to drain.

3. Your engine “bangs” and misfires

When your engine misfires it causes the vehicle to halt for a fraction of a second and then continues it’s usual movement, this means the vehicle isn’t functioning as smoothly as it should because one or more of your engines cylinders aren’t firing properly, this can lead to other issues such as higher emissions which potentially would cause your car to fail it’s MOT.

4. You notice high fuel consumption

If your spark plugs have deteriorated or are faulty then you’ll notice that your vehicles fuel economy can decrease hugely due to incomplete combustion cycle. If you notice you’re having to fill your cars patrol tank more often than usual it can be caused by deteriorating spark plugs. To get back to your vehicle’s optimum level of fuel consumption all you’ll need to do is have your spark plugs changed.

5. Your car has a lack of acceleration

If your vehicle is accelerating poorly it is fairly easy to tell. It feels as if the vehicle doesn’t want to respond when you put your foot down, or it does but not instantly as you’ve become accustomed to, It can also feel as if your vehicle is trying really hard to pull itself along. This ‘sluggishness’ can be easily fixed by having the vehicle serviced with a spark plug change.

How much do spark plugs cost?

Spark plug costs can vary from car to car and brand to brand, getting your spark plugs replaced isn’t something you need to worry about often however the cost of maintaining these key components can save you a small fortune compared to neglecting them and having the knock on effects of faulty spark plugs do damage to other parts of your engine.

Should I Change My Spark Plugs Myself?

Changing spark plugs is not a hugely difficult job to complete but you will need some tools and to follow the following steps to correctly change them.

  • Ensure the engine is cool before attempting any work.
  • Locate the spark plugs in your car, positions will vary depending on 4 cylinder, 6 cylinder inline or V6 / V8 engine type.
  • Remove the lead attached to the top of the first spark plug.
  • Using a socket set remove the first spark plug and check for obvious damage/ discolouration.
  • Measure the gap on the spark plug, the gap should be between .028-.060 inch, this will vary dependant on the type of plug and the car.
  • If the plug needs replacing then clean the area and replace with new plug.
  • Repeat for all other plugs.

Should you not wish to get into the checking, measuring and replacing of your cars spark plugs simply book an appointment and one of our skilled technicians will have your car running and back to normal in no time.



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