Spark plugs are, quite literally, the spark that keeps your engine firing smoothly.
They are integral to a smooth drive as they ignite the fuel-air mix in combustion engines, providing the power you need.
If they aren’t changed when they’re past their effectiveness, it could introduce problems for your engine.
What do spark plugs do?
Each plug screws into the top of every cylinder in your engine.
So if you have a four-cylinder engine, you’ll have four plugs, while a six-cylinder engine has six and so on.
The part of the spark plug that sticks into the cylinder is the terminal – where the spark is generated.
The electricity generated by the car’s ignition system first flows through the centre electrode, one of two.
When the electricity jumps the gap between the centre electrode and the second one, a spark is formed.
That ignites the fuel-air mixture at the optimum time within the cylinder, forcing the piston down and turning the crankshaft.
When is it time to change them?
To be clear, spark plugs don’t need to be changed very often and are designed to withstand huge amounts of punishment.
Some cars only need replacement spark plugs after 100,000km, some up to 120,000km.
Refer to your owners’ manual: it will recommend when you need to replace your engine’s spark plugs.
Different materials have different lifespans: copper wears out the fastest, while iridium- or platinum-tipped plugs last the longest.
However, no matter what material, spark plugs are exposed to high temperatures and pressures and develop wear and tear after repeated sparkings.
Carbon deposits can build up on the electrodes, affecting the sparking efficiency and hence, engine effectiveness.
Here are six tell-tale signs your car needs new spark plugs:
- When your engine sounds rough at idle.
- When you have trouble starting your car, ie when the engine doesn’t ‘catch’ at the first press of the ignition.
- When you feel the engine misfiring, ie power halting for a split second and then continuing.
- Jerky performance from the engine.
- Lack of acceleration: if you feel your car moving away slower than usual from the lights, it might be time for new spark plugs.
- Higher fuel consumption because of incomplete combustion within the engine due to worn-out plugs.
In addition, be sure to check the electrical leads (wires) leading to the plugs themselves.