Spark Plug FAQs

Everything you need to know about Spark Plugs

What do spark plugs do?

Think of spark plugs as the tiniest bolt of lightning. Small but might, the spark of electricity that the plug emits across a small gap creates the ignition for the combustion needed to start your car. By putting the engine’s pistons in motion, your car can power up, stay powered up and produce a smooth burn of the compressed air-fuel mixture. Mind you, spark plugs like it hot: they withstand extreme heat and pressure within your cylinders and are built to burn off deposits from fuel additives or other contaminants.
This means that without a spark, your car won’t start – or go anywhere. And because spark plug health is directly linked to engine performance, it stands to reason weak or bad spark plug lead to problems, be it issues with cold-starting or misfires during acceleration. Besides- without healthy ones- your car can’t sustain maximum power, and your vehicle can see a drop in fuel economy.

How often should spark plugs be replaced on my vehicle?

Luckily, spark plugs don’t require replacement very often and can go years and many miles before replacement is a must.
Most auto manufacturers suggest having new spark plugs installed about every 30,000 miles; however, spark plug longevity depends on the condition and type of spark plug. Copper plugs, for example, have the shortest life, while plugs made of more advance and durable materials can provide up to four times the life of a copper spark plug.

What happens to a spark plug as it ages?

By the time spark plugs reach old age, they’ve spent thousands of miles enduring abuse and withstanding the most extreme temperatures and conditions to stay intact. That’s where the importance of spark plug material comes into play. The stronger the material, the more durable and long-lasting the spark plug. Naturally, though, every spark plug undergoes wear and tear, materials aside.
Spark plugs can’t last forever, and here is why:

Spark plug deposit build-up: When deposits form on spark plugs from interaction with the air=fuel mixture, it can lead to pre-ignition of the fuel. That means a jerky and unreliable supply of energy for your car.
Expanding, harder-to-jump gap: When a spark plug ignites it has to travel across a gap of space in order to provide the right level of combustion at the right moment. As spark plugs age, this gap widens as a result of extreme temperatures, debris and normal wear and tear. If the gap is too far apart, combustion will be erratic or ineffective.

What is the benefit of replacing a spark plug?

The primary benefit is knowing your car will start without a hitch. Needless to say, that’s not all that matters. New spark plugs provide a lot of other performance benefits as well.
New spark plugs will lead to:

Consistent production of optimal combustion. Fully functioning spark plugs equate a fully functioning combustion system. Get this operating successfully, and a lot of performance issues you’re experiencing could be a distant memory.
Smooth and energetic starts. The first time you turn the ignition with a new spark plug can be an eye-opening experience. That old spark plug may have been the reason your car was experiencing those jerky starts.

How involved is spark plug replacement service?

The complexity of a spark plug exchange varies from straightforward to being very involved. Your vehicle must be worked on when the parts are cold, and the amount of time it takes to complete varies by make and model. In some cases, it may be necessary to disassemble vehicle parts in order to reach your spark plugs. Plan ahead, because a vehicle drop-off is usually required.

What symptoms may indicated my vehicle’s spark plugs need replacing?

Rattling, pinging or “knock”-like noises. When spark plugs begin to misfire, you may notice unusual noises from the force of the pistons and combustion not working properly. Pistons travel at high velocities. If the spark plug fires at the wrong time, this could lead to constant rattling, pinging or knocking sounds.
Hard vehicle start. If your car is having trouble starting or just feels disjointed and jerky, your spark plugs may not be working right, and this can lead to misfires and erratic performance.
Reduced performance. When you’re out cruising, your spark plugs fire when you accelerate and change gears. If the spark that this little plug generates isn’t functioning at 100 percent, your vehicle performance will be poor, and you’ll experience a sluggish and fuel-wasting drive.
Poor fuel economy. Lots of things can lead to poor fuel economy, though when it comes to old spark plugs, you’ll find fuel is wasted since your vehicle fails to receive the proper, heat-generating spark at the right time.

If you have spotted any of these symptoms, we suggest having your vehicle inspected in order to prevent further problems. Healthy spark plugs are vital to your car’s ability to start up and remain powered.

Can’t I just get a tune-up, like the old days?

Back in the day, a tune-up meant replacing spark plugs, spark plug wires, the distributor, distributor cap, rotor and points and condenser in addition to setting the timer and adjusting the carburetor. Nowadays, though, your car’s computer does most of the heavy lifting, leaving you to worry most about the spark plugs and fuel injector, sensors and switches.
It is important to note the modern “standard” tune-up, today, means changing your spark plugs.
Our standard tune-up includes:

Visual inspection of your engine components
Installation of Bosch spark plugs
Timing and idle set (if necessary, though most of today’s vehicles have computer systems adjust these automatically)