Do We Really Need To Change Spark Plugs On Every Servicing?

It’s car servicing time yet again. You take your car to your mechanic. He opens its innards, shakes his head and mutters a few unintelligible words and then hands you an estimate. And nine times out of ten you dish out the money without even knowing what you are paying for. Of course a brand new spark plug always features in the bill.

Well before we answer that question, let us see what a spark plug does.

Light my fire
Most cars, except the new fangled electric ones (and we are really not discussing those) work with an internal combustion engine. A mixture of fuel and air is fired up in a series of controlled explosions. And the energy produced by these explosions is what powers your car.

The spark plug plays a crucial function. It provides the flame or the fire for this process.

How long does the spark last?
Truth be told, no one knows. It all depends on the individual spark plug, your car and the way you drive. But as your spark plug gets older, it does start losing its spark. The electrodes are slowly worn away. The gap between the two points increase and the electric charge needed to fire it up also increases. So normal copper spark plugs last between 10,000 to 20,000 miles. While the high end platinum or iridium plugs can carry on till 60,000 miles!

Time for a new one:
However no matter how great or expensive your spark plug is, there will come a time when you need to change it. You can tell by these warning signs.

Your car loses its steam:
You push down on the accelerator pedal – nothing happens. Or maybe your car does speed up but very lazily. It almost feels as if your car has been replaced by its sluggish twin.

More gas per mile:
Your car suddenly develops a great thirst and seems to be guzzling up more fuel (up to 30%). No it is not the Singaporean summer which is causing this thirst, but a faulty spark plug. The spark plug is not being able to fire up the fuel and air mixture at optimum efficiency and hence more fuel consumption. More emissions, more pollution: Is your car suddenly acting naughty? Has it all of a sudden become an environmental disaster? Again an inefficient firing up of the air fuel mixture could be causing this rise in emissions. And behind all this – a faulty spark plug.

Your car jerks you around:
Sudden jerks in the otherwise smooth drive could be caused by engine surges. Sometimes the car slows down and comes to a stop suddenly and then starts up again. Quite tricky in a traffic situation and dangerous too. This is also called engine hesitation.


Misfiring engine:
Your car engine halts for a moment and then starts up again. This could mean that your car cylinder misfiring. Time to visit the mechanic and get your spark plugs changed.

A rough idle:
Usually when your car engine is idling, it will emit a smooth (and to some, melodious) sound. However if the engine sounds out of tune or the volume gets higher than usual, you probably need to get a check up.

Your car refuses to wake up:
You wake up in the morning and start the car but your car continues to sleep. Is it out of fuel? Is the battery dead? The problem might be in your spark plug.

Car servicing time: check, don’t change:
So the next time you go in for a car servicing, you may need to change your spark plug. Or you may not. It all depends on what state it is in. If your spark plug is still relatively new and functioning perfectly insist that you want to be loyal to it for some more time. If the mechanic feels that it needs to be changed, ask him why.

Clean, not change:
Sometimes all your spark plug needs is a good scrubbing with sandpaper. Soot and grease might have collected on it and is reducing its efficiency. So before opting for a new one, make sure that your mechanic gives the old one a thorough cleaning. Better still, learn to do it yourself – it is ridiculously easy.

So change or not?
So do we really need to change spark plugs at every servicing? Most certainly not. But it is best to get it checked to ensure that your car works the way it is supposed to work.