Idling Causes Damage to Spark Plugs and More

As the saying goes, idle hands are the devil’s playground. If that’s true, then idling engines might just be a fool’s playground. Contrary to common belief, an idling engine is doesn’t warm up your engine or save gas, and it can wreak havoc on your engine’s parts. E3 Spark Plugs offers a few myth-debunking tips.

If this guy's engine is idling too, he's wasting much more than time.

Many people are, for reasons unknown, convinced that idling your engine for several minutes consumes less fuel than turning off and restarting the engine. Fact is, for every two minutes that a car is idling, it uses about the same amount of fuel that it takes to go nearly a mile. Research indicates that the average driver idles his engine five to 10 minutes a day. Add up all the days of the month or year and it’s clear – that’s a lot of wasted fuel.

Experts recommend turning off the engine if you’re going to be parked for more than 30 seconds. Ten seconds of idling can burn more fuel than turning off and restarting the engine. Plus, excessive idling can damage your engine’s components, including spark plugs, cylinders and exhaust systems. Because your vehicle’s engine is not operating at its peak temperature when idling, fuel is only partially combusted, leading to a fuel residue buildup on cylinder walls. This is the gunk that can foul your sparkplugs and muck up your exhaust systems.

You’ve probably also been told that frequent restarting is hard on your engine. Fact is, it has little impact on engine components like your battery and starter motor. Component wear caused by restarting your engine is estimated at about $10 – far less than the money wasted on the zero-mileage fuel consumption caused by idling.

“But it’s freezing,” you say? Even in when the weather’s cold, today’s engines need no more than about 30 seconds to be ready for the drive. Plus, driving – not idling – is the most effective way to warm up your engine anyway.

By the way, your engine isn’t the only thing negatively affected by excessive idling. Medical studies show that idling is linked to increases in asthma, allergies, heart and lung disease and cancer. So turn off your engine – it’ll save you much more than spark plugs.


A close-up view of a brand-new nickel electrode spark plug for an automotive internal combustion engine.
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