Spark plugs are one of those car parts most people don’t think about until something goes wrong. They’re small, inexpensive, and easy to overlook—but they play a big role in keeping your engine running smoothly. If your spark plugs are worn out, your car won’t perform the way it should, and ignoring them for too long can even lead to bigger (and more expensive) problems.
So, how do you know when it’s time to replace them? Let’s break it down in simple terms.
What Do Spark Plugs Actually Do?
Every time you turn the key (or push the start button), your spark plugs ignite the fuel and air mixture in the engine. Without that spark, your car won’t start. They fire thousands of times per minute when you’re driving, which is why they eventually wear down.
Think of them like the matches that light your BBQ—without a good spark, nothing happens.
Signs Your Spark Plugs Need Replacing
Here are a few telltale signs you might be due for new ones:
- Difficulty starting – If your car struggles to start in the morning, worn spark plugs could be the culprit.
- Rough idling – Does your car feel shaky or sound uneven when sitting still? Bad plugs can cause misfires.
- Poor fuel economy – Worn plugs don’t burn fuel efficiently, which means more trips to the servo.
- Lack of acceleration – If the car feels sluggish when you hit the pedal, the spark may not be strong enough.
- Engine warning light – Sometimes, a failing spark plug will trigger the check engine light.
How Often Should You Replace Them?
There’s no one-size-fits-all answer. It depends on your car’s make, model, and the type of plugs it uses.
- Standard copper plugs may last around 20,000 to 30,000 km.
- Platinum or iridium plugs can last up to 100,000 km.
The best advice? Check your car’s manual. It will tell you the recommended replacement schedule. In Australia, most people end up changing their plugs every few years, depending on how much they drive.
Why Replacing Spark Plugs Matters
Fresh spark plugs keep your engine running efficiently, which means:
- Better fuel economy.
- Smoother starts.
- Reduced emissions.
- Less chance of costly engine damage down the track.
We once had a customer who ignored spark plug issues in his old Commodore. By the time he brought it in, the misfiring had caused damage to the catalytic converter—a repair that cost far more than a simple spark plug replacement would have.
Can You Replace Them Yourself?
If you’re handy with tools, changing spark plugs can be a DIY job. But for many modern cars, access to the plugs isn’t as straightforward as it used to be. If you’re unsure, it’s worth letting a mechanic handle it during your next service. The cost of replacement is usually low compared to other maintenance jobs.
Before You Start Wondering About Your Spark Plugs
If your car is harder to start, using more fuel, or just not running as well as it used to, it might be time to give those spark plugs some attention. A quick check and replacement could bring your car back to life and save you money in the long run.
If you are in Toorak, and looking for a cash for cars service, this is the best way to visit us.
(03) 7047 6388