Original Video/spark plugs 7 months ago VIDEO: Spark Plug Insulators And Flashover Share Tweet Print Email ImportCar Staff Writers,administratorView bio Bio Recent Posts Popular Posts WAI Launches A Smarter Mass Air Flow Sensor ProgramArnott Introduces New Front Air Struts For The 2007-'13 Mercedes-Benz S-Class, Mercedes-Benz CL-ClassManagement Success Fall Convention Focuses On Hot TopicsMAHLE Announces Schedule For AAPEX 2017Expanded Tenneco eLearning Platform Created To Help Shops Target, Sustain Growth In Ride Control Category Mazda, DENSO And Toyota Sign Joint Technology Development Contract For Electric VehiclesPhilips Unveils Ultinon LED, A New And Advanced Generation Of Automotive Lighting, Company SaysCheck Out The September Issue Of ImportCar MagazineAutel Issues New TPMS Updates For TS508, TS608ALI Moves Into Larger Headquarters, Opens LiftLab 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.