Spark Plugs
Replacement to the correct plug type and gap for your engine — the usual cure for a rough idle, misfire or a quietly worsening fuel bill.
A spark plug fires tens of times per second, every second the engine runs. The electrode gradually erodes and the gap it has to jump grows wider, which means the ignition system works harder for a weaker spark. The result creeps up on you: slightly rougher idle, slightly worse fuel economy, then a misfire and a check engine light.
The plug type matters as much as the change interval. Copper plugs are inexpensive but wear quickly; platinum and iridium last far longer because their electrodes resist erosion. Fitting the wrong heat range or gap causes running problems of its own, so we match the manufacturer's specification for your engine rather than whatever is on the shelf.
What's Included
- Removal and inspection of the existing plugs — their condition tells us a lot about how the engine is running
- New plugs of the correct type, heat range and gap
- Ignition coil and coil boot inspection
- Torque to specification, which matters on aluminium heads
- Anti-seize and dielectric grease applied where appropriate
When You Need This Service
- Rough or uneven idle
- Engine misfire, hesitation or stumbling under acceleration
- Harder starting, particularly on cold mornings
- Fuel economy that has quietly got worse
- Check engine light reporting a misfire code
Frequently Asked Questions
How often do spark plugs need replacing?
It depends entirely on the type. Copper plugs typically last 30,000 to 50,000 km, while iridium and platinum plugs can run to 150,000 km. Your owner's manual gives the figure for your engine, and we work to that rather than a generic interval.
Can worn spark plugs damage the engine?
Indirectly, yes. A persistent misfire dumps unburnt fuel into the exhaust, which can overheat and destroy the catalytic converter — a repair far more expensive than a set of plugs. It also puts extra load on the ignition coils, which then fail in turn.
Do I need to replace ignition coils at the same time?
Not automatically. We inspect the coils and boots while the plugs are out, since a failing coil often shows up as a misfire on one cylinder. If a coil tests fine, it stays. If it is cracked or breaking down, we will show you why it needs replacing.