The Spark Plug Myths You Should Stop Falling For – Jalopnik

The spark plugs in your car’s gasoline engine are remarkably durable and can last dozens of oil changes before needing to be replaced. For components that can withstand intense heat, pressure, high-voltage electrical currents and vibration, spark plugs typically go unnoticed until something goes wrong.

They are quite small, but they do big things for your engine, and without them the combustion process would not be complete. Despite their wear-resistant nature, all spark plugs will eventually fail. The most common signs that your engine needs new spark plugs are difficulty starting, poor fuel economy, lackluster acceleration, and a general feeling of engine lethargy.

Spark plugs wear out at different rates, so claims that engines need new spark plugs every 20,000 or 30,000 km are nonsense if we don’t know what type of spark plugs are in the cylinder head. Additionally, you can clean and reuse old spark plugs, but don’t expect them to last as long or provide the same level of performance as new spark plugs. Just as there are several myths about motor oil that won’t go away, there are also several persistent myths about spark plugs. Here are the spark plug myths that are just that: myths.

For example, downgrading to incompatible platinum or copper spark plugs in an engine that requires iridium will certainly lead to performance variations, idling problems, excessive engine vibration, and premature spark plug wear. Meanwhile, spark plug size has to do with wire diameter, range and socket size, so you can’t just swap the spark plugs from a Toyota V6 to a BMW inline-six and expect them to fit and work perfectly.

And even if any spark plug fits into the cylinder head, that doesn’t mean it will continue to spark without causing a whole host of problems. Spark plugs have a hot and cold heat range, and using the wrong type can foul the spark plug tips with carbon deposits or pre-ignite the air-fuel mixture, which is bad news for your engine as well as your bank account. There is no one-size-fits-all solution when it comes to spark plugs, so it is best to consult your owner’s manual to determine the correct type, size and heat range for your engine.

It’s a similar deal with spark plugs. They don’t last forever, although some can travel more miles before they wear out completely. The plugs will mainly wear out and fail due to overheating or carbon buildup, but some can last longer than most. Simple copper spark plugs need to be replaced every 20,000 to 20,000 miles, but platinum and iridium spark plugs are stronger and can last about 100,000 miles. Yes, spark plugs are long life components, but they don’t last forever (because nothing does).

Wrong. You can replace only one spark plug if you want, but that does not guarantee a smooth-running and reliable engine. For starters, mixing new spark plugs with old ones can throw your car’s ignition system out of balance, potentially leading to misfires and poor fuel economy. Additionally, a single worn plug means the others are likely on their way out, so it is wiser and more economical to replace them all at once rather than one or two at a time.

Of course, it’s fine to replace just one spark plug if you’re in a pinch or in an emergency situation, but keep in mind that this is only a temporary fix and not a long-term solution. Replacing all the spark plugs at the same time is a surefire way to prevent future engine problems and more expensive headaches.

But don’t expect your engine to magically produce more horsepower and torque, as performance spark plugs won’t necessarily produce a noticeable increase in horsepower. Iridium plugs are more about efficiency than adding power, and you’re essentially paying for longevity rather than an energy-boosting modification.

Engines didn’t just appear out of the blue with copper, platinum or iridium plugs. The type of spark plugs was specifically chosen by the engineers who designed and built the engine, and they did this to ensure the reliability, ease of maintenance and performance of the engine. Therefore, there is a hard science as to why your motorcycle has that type of plug, and no myth should get in the way of that.