Original Video/spark plugs 4 months ago VIDEO: Spark Plug Insulators And Flashover Share Tweet Print Email ImportCar Staff Writers,administratorView bio Bio Recent Posts Popular Posts Mini Pry Bar Set Now Available From Cal-Van ToolsCheck Out The August Issue Of ImportCar MagazineRepairPal Launches New Shop Dashboard For Shop OwnersAAPEX 2017 Mobile App Now AvailableGabriel Introduces New Website Training Resources Matco Offers 12V Cordless Infinium Impact Driver KitCheck Out The July Issue Of ImportCar MagazineBogi From All Girls Garage To Host 2nd MAHLE Aftermarket Facebook Live EventStandard Motor Products To Award More Than $10K In Prizes During The 'Why I Trust Standard' GiveawayAccess Glow Plugs With Baum Tools Pliers Andrew Markel shows the importance of keeping a spark plug’s insulators clean to prevent flashover. Sponsored by Denso. Gabriel Velazquez Flashover happens because the cop boot is crying uncle, and nobody ever sells customers new coil boots, because the industry has not made it a known serviceable item. Whenever you hear tune up these days, nobody mentions new coil boots, which usually fail long before a vehicle even needs spark plugs. I have seen them leave tracing in as little as 25k miles. You have to be an absolute slob to gunk up a plug enough where it would cause flashover. Some smudging on a plug will not do anything.