Anti-fouling spark plug and method of making

A spark plug comprising

• an insulative sleeve having a central axial bore and an exterior surface, wherein a coating is disposed on the exterior surface and the coating comprises a silicone resin and an inorganic filler in the form of fumed silica;
• a center electrode extending through the central axial bore of the insulative sleeve;
• a metal sleeve, wherein the insulating sleeve is positioned within, and secured to, the metal shell;
• and
• a ground electrode supported by the metal shell and positioned in a spaced relationship relative to the center electrode so as to generate a spark gap.

A spark plug comprising

• an insulative sleeve having a central axial bore and an exterior surface, wherein a coating is disposed on the exterior surface and the coating comprises a silicone resin and an inorganic filler, wherein a ratio of a mass of the inorganic filler to a mass of the silicone resin is at least 1:1;
• a center electrode extending through the central axial bore of the insulative sleeve;
• a metal sleeve, wherein the insulating sleeve is positioned within, and secured to, the metal shell;
• and
• a ground electrode supported by the metal shell and positioned in a spaced relationship relative to the center electrode so as to generate a spark gap.