Can You Clean And Reuse Old Spark Plugs?

Atitaya Pimpa/Getty Images

There's thing oddly satisfying astir pulling an aged spark plug retired of an engine, but what do you do pinch nan plug erstwhile it's out? Maybe you're having 2nd thoughts about changing nan spark plug altogether. It's covered successful carbon, sure, and possibly a small lipid aliases rust if things person gone really wrong. Still, you can't thief but think, "Hmm — possibly it's not done yet."

Logically, yes, you tin cleanable and reuse a spark plug but it depends connected really acold gone it is. A small c fouling aliases barren soot? That tin beryllium mildly wire-brushed off. Some group successful forums committedness by blasting them cleanable pinch carb cleaner and giving nan electrode a ray touch-up pinch sandpaper. Others spell afloat huffy intelligence and usage plug-specific media blasters for illustration sand, to get them backmost to like-new condition.

However, spark plugs don't conscionable deterioration retired connected nan surface. The crisp edges of nan electrode erode. The spread widens. The insulator degrades from power cycling. So while you tin cleanable them up, what you're doing is simply a impermanent hole astatine best. You simply won't get nan aforesaid usability from nan cleaned plug versus a caller one. It mightiness beryllium okay for testing aliases nursing an aged car done 1 much season, but reusing a borderline plug successful a high-compression motor aliases modern ignition system? Probably not worthy nan risk.

YAKOBCHUK VIACHESLAV/Shutterstock

Old motorcycle? Lawn mower that hasn't seen synthetic lipid successful decades? Sure, cleanable nan plug and put it backmost in. In low-demand engines aliases diagnostic situations, a reused spark plug tin beryllium perfectly acceptable. Just don't expect miracles. You're conscionable delaying nan inevitable.

In modern cars — particularly those pinch coil-on-plug ignition, nonstop injection, and turbochargers — spark plugs request to beryllium perfect. These engines request precision timing, and moreover a somewhat worn aliases fouled plug tin lead to misfires, unsmooth idle, and mediocre substance economy. On turbocharged nonstop injection engines, low-speed pre-ignition (LSPI) is simply a existent threat — this is erstwhile combustion starts earlier nan spark plug fires, it creates utmost unit and power that tin destruct pistons successful seconds. Researchers person documented LSPI extensively, noting its relationship to spark plug and combustion enclosure creation successful boosted nonstop injection engines. 

Suddenly, that $10 savings doesn't look truthful smart. Cleaning aged plugs pinch abrasives aliases harsh devices tin besides harm nan firing extremity and portion distant captious coatings, which are portion of what make newer iridium and platinum plugs past truthful long. A plug mightiness look good to nan naked eye, but erstwhile that coating is compromised, its reliability drops fast.

If you're conscionable diagnosing an rumor aliases stranded and trying to get home, reuse it. If you're doing a tune-up? Just replace nan spark plugs. Most modular plugs are cheaper than your adjacent vessel of gas. 

stella_photo/Shutterstock

Spark plugs stay a inexpensive yet captious attraction point connected a car. So, yes, cleaning tin revive a plug for a bit, but it's seldom a reliable semipermanent strategy. Manufacturers explicitly urge replacement complete cleaning to guarantee accordant motor performance. While copper spark plugs mightiness only past up to 30,000 miles, platinum spark plugs could spell up to 60,000 and iridium plugs tin agelong up to 100,000 miles. Ultimately, nan occasional spark plug replacement is a mini value to salary for bid of mind.

While forums and anecdotal proposal supply plentifulness of techniques for cleaning spark plugs — from brushing to blasting — moreover astir DIY mechanics work together that they are champion utilized arsenic backups. They mightiness get your motor to move complete successful a pinch, but they're not nan benignant of portion you'd want successful your regular driver erstwhile you're chasing reliability.

So yes, you tin cleanable and reuse aged spark plugs. However, unless your extremity is conscionable to get nan car moving 1 much clip to return it to nan scrapyard, buying caller ones is nan amended bet. Don't dainty them for illustration reusable zip ties. The value of a caller group is already low. The costs of dealing pinch misfires, unsmooth idles, and declining substance economy? That gets costly existent fast.